What works on one child may not work on the others.
Besides that, i also found an interesting article on dicipline approach according to ages which was prepared by Judith Graham, Extension human development specialist.
Discipline that Works: The Ages and Stages Approach
|Age||Development of Emotions||Tips|
|Infancy||Stable, well-balanced periods occur around 4, 16, 28, 40 and 52 weeks. Periods of imbalance occur often around 8, 20, 32 and 44 weeks.||No discipline needed.|
|18 Months||Acts on impulse. Is insistent, demanding. Not much trouble with own emotions, but has trouble with other people’s. Wants own demands met here and now. Not very adaptable or cuddly. Easily frustrated; attention span extremely short. Loves the outdoors and carriage/stroller rides.||Doesn’t easily obey direct commands. Get attention by doing something child likes and wants to share. THINGS TO TRY: Pick up and put child where wanted. Distraction.|
|21 Months||More demanding and less adaptable. Dependent. Has strong needs and demands, but cannot communicate them. May resist being touched.||Need for great patience and wise assessment of capabilities; discipline is not the important thing at this age. Arrange to just get smoothly through the day. THINGS TO TRY: Most successful are physical; rearrange the setting to avoid problems. Talking to them usually doesn’t work.|
|2 Years ||Less demanding. More adaptable. Tends to be quiet and calm. Willing to cuddle and accept affection.||Take advantage of child’s rituals, especially at bedtimes; use security items the child likes (thumb, blanket, etc.). THINGS TO TRY: Distract them or change the scene.|
|2 1/2 Years||Great imbalance. Moves between extremes of aggression and withdrawal. Bossy, rigid, selfish, possessive, jealous. Likes sameness, repetition, predictability; changes are very hard, even minor ones; toys, etc. all have a “proper place.”||Age of opposite extremes. THINGS TO TRY: Avoid giving choices. Avoid questions that can be answered by no. Use routines. Talk and work fast so child will be doing what is wanted before she or he has time to think and rebel. Anticipate difficult times or situations and avoid if possible; do not expect your child to wait for things or to share easily.|
|3 Years||Often time of emotional calm. May be happy, contented much of the time. Gets along well with others. Likes others and wants to please them.||THINGS TO TRY: Enthusiasm, good-will and common sense.|
|3 1/2 Years||Difficult age. Is uncertain, unsettled, insecure, yet is stubborn, demanding, unwilling or unable to give in or adapt. Tends to be fearful, unhappy. Child’s big emotional struggle is with his/her mother (she is the only worthy opponent); enjoys talking/conversation; time of great motor uncertainty and fluctuating fine motor capabilities. At this age, children are much better with almost anyone other than the principal caregiver.||Difficulty making changes. May be good in long periods of play, but very poor at changing from one activity to another. THINGS TO TRY: Simplify changes as much as possible. Avoid head-on clashes. Let him know he is great — the best child ever; emotions may be very fragile; may express fears or anxieties about the dark and animals — support these but do not encourage; use an imaginary companion to help get things done; heavy use of positive phrases: “let’s,” “how about,” and “maybe you could.” Give in when things aren’t important. Change subject or distract by bringing in something nice so child forgets to object.|
|4 Years||Energetic, out-of-bounds. May go to extremes to test self against others. Often enjoys own impish, humorous ways. May be selfish, rough, impatient, loud. Loves adventure. Socially silly and larger-than-life manners may annoy adults.||Delights in upsetting adults. THINGS TO TRY: Ignore profanity, boasting, super-silly way of talking, if possible; enjoy her silliness and participate; usually likes and respects boundaries and limits; bargaining works well; surprises are good motivators; whispering very effective; praise and compliments work wonders as does the simple art of conversation. Make few rules, but enforce these strictly.|
|5 Years||Tends to be calm, quiet, well-balanced. Pulls in and usually tries only what he knows he can do, so is comfortably well-adjusted. Friendly, loving, appreciative, wants to please and do the right thing; wants and means to be good; not yet able to admit to wrongdoing and as much as he tries, does not always tell the truth.||Let them know what is and is not reasonable to expect. Many things parents consider bad are often simply immaturities. THINGS TO TRY: Prevention is much better than punishment. If you punish, do so calmly. Child’s wish to be good and do the right thing is strong. With luck, there should be relatively little need for punishment.|
|5 1/2 to 6 Years||Highly emotional. Not in good balance. Loves one minute, hates the next. Much confusion and trouble between self and others. May demand, rebel, argue, fight. When in good mood, is cheerful, energetic, enthusiastic. Needs much praise, but behavior often merits criticism. This only makes behavior worse. Not able yet to tell the difference between mine and yours.||Age of extreme imbalance. May be very rude, resistant, defiant. Thrives on head-on clashes. Punish if absolutely necessary, but calmly. THINGS TO TRY: Patience and skill. Ignore refusal or be impersonal when child answers commands with “I won’t.” Praise — it may not be easy to find something to praise but try hard; avoid resistance and head-on collisions; sidestep issues if possible; bargain; give in on occasion.|
|6 1/2 Years||Behavior quiets down for a few months. Usually relates strongly and warmly to adults close to them. Brief periods of being happy with themselves. Money is becoming of real interest both as an allowance and as a reward. Eager for more possessions.||THINGS TO TRY: Small rewards for little chores or even eating a good meal. Give them “chances” to get a request done. Consenting and bargaining also work well.|
|7 Years||Quiet, rather negative emotions. May be serious, self-absorbed, moody, worrisome, or suspicious. Very sensitive to others’ emotions. May feel disliked by others and that they are critical or poking fun. Procrastinates, has a short memory, and is easily distracted; often completely tunes out the outside world.||Obedience problem may be because child is sidetracked. THINGS TO TRY: To have a simple chore done, tell child in advance. Be sure they heard the directions. Remind the child before he or she forgets and does something else.|
|8 Years||Vigorous, dramatic, curious, impatient, demanding. Not as moody as 7, but still sensitive. Very demanding of parents, especially mother; strongly influenced by her wishes and desires; wants time, attention, affection and approval; beginning to think abstractly; interested in and concerned about own possessions. Easily disappointed if people don’t behave as wished. Can be quite critical of others and self. Argumentative.||Easily disappointed if what an adult says or does isn’t what the child wants. THINGS TO TRY: Give commands in ways acceptable to the child. Money is a good motivator, as are time, attention and approval.|
|9 Years||Quieter than at 8. Seems to be independent, responsible, dependable, cooperative. May sometimes be temperamental, but is basically reasonable. May be age of considerable rebellion against authority; tend to go to extremes; will take criticism fairly well if carefully phrased; great interest in fairness; group standards may be more important than parental standards. Demanding of others, but likely to be as critical of self as of others. Very involved with self and may not hear when spoken to. May appear absent-minded or indifferent. Shows anger at parents, but is also proud of them, is loyal to family, friends. May show concern for others.||Interests are beginning to spread beyond home and family. May resist feelings of being a little child and of being told what to do. THINGS TO TRY: Save direct commands for big important matters.|
|10 Years||Emotionally direct, simple, clear-cut, usually well-balanced, yet still childlike. Less anxious and demanding than at 9. Most often good-natured and pleased with life. But may show sharp, violent temper. Can be very affectionate. Not a worrying age, yet a few earlier fears remain. Enjoys own humor, which may not be very funny to others. Happy age.||Tricks or specific and special ways of approaching a child are no longer particularly useful; involve the child’s ability to distinguish good from bad, right from wrong, truth from untruth; best technique is to know what is reasonable to expect.|
Source: Ames, L.B. (1992). Raising Good Kids: A Developmental Approach to Discipline. Rosemont, NJ: Modern Learning Press.
It also says that. "Implementing effective discipline is not always easy and takes some practice. Don’t get discouraged! Remember, if you don’t get the results you want, think the situation through and try again."
I will definitely try and will never lose hope.