Difficulty: Moderately Challenging
Step1
The first thing you will need to do is find out a way to do assisted pull ups. There are many ways to do assisted pull ups. If you go to a gym there will no doubt be a lat pull down machine, but even better would be an assist pull up/dip machine. This machine will have a pull up bar and a platform you stand or knee on with adjustable counter weights to make the lift easier.
Step2
Another great way to do assist pull ups is with a strength band. Strength bands come in many "weights" and can give help from 5 pounds all the way up to 200 pounds. If you work out at home or don't have an assist pull up machine simply purchase a couple of these bands. You will want one at a light weight and one at a medium weight so that you can combine them to start, then use the medium one and finally just use the light one before performing pull ups solo.
Step3
Once you have your assist simply follow this routine for 8 weeks. If at the end of the 8 weeks you aren't strong enough to do a full pull up yet that's okay, simply continue on until you complete your first pull up. Once you get the first one, more pull ups will come easier.
Step4
Monday, Wednesday, Friday
5 sets of pull ups in 10,8,6,4,2. This means at each set raise the weight so that the number of reps is difficult but doable. The first set should be ten reps, the next set should be eight reps and so on.
Step5
5 sets of negatives. To do this, use a chair or someone lifting you up to get chin above hands, then let yourself back down to a lockout as slowly as possible.