S.H.
Good link from baby center.
Also, keep in mind that "impulse control" is NOT fully developed in a child this age. FULL impulse control is not even "fully" developed until about 3+ years old.
Right now at this age, everything is sort of "reactive." Toddlers are "reactors" and cause and effect. This is how they learn, experiment, express curiosity, "control", independence etc. yada-yada-yada.
Okay so, yes, sure, the tips via Baby Center ARE great... because kids learn by REPETITION and CONSISTENCY. But remember, there will be LOTS of repetition as you "teach" him not to pull hair or other things. You will feel like a broken-record. But, keep instilling things in him that are important to you and him.
In time, a child will learn and get better about their reactions and impulses. BUT, it won't always be perfect, they won't always do it correctly, they won't always listen, they won't always understand perfectly, they won't all the time.
But, give him credit for when he IS "trying his best." For some kids, they think they have to do something "perfectly"... and so, it's a lot to do, and so they just don't. So, at least with our kids, we emphasize "doing your best..." instead of doing it "perfectly." That way the child will see that something IS ATTAINABLE.
And likewise, always keep things age-appropriate, AND your expectations "of" him age-appropriate.
To me, "time-out" at this age and then expecting him to act accordingly will not work, due to his age and cognitive "maturity" at this age.
Its also a phase... which, who knows how long phases last... each child is different.
Some kids even push, bite, hit. But your son pulls-hair. Slow and steady, and consistent... is what I would suggest as far at modeling for him and "teaching" him... in time.
Good luck,
Susan