As far as pull ups, I use a backpack with 30 lbs in it. My routine starts off with a warm up set of ten with no weight. After that set is complete, I do five sets of 5 using the full 30 lbs. I then take out 10lbs and do 3 sets of 10. Lastly, I do my set with no weight and try to perform 15 reps.
This took me from 15 pull ups to 21 in six weeks.
Weighted pull-ups are definitely the way to succeed.
My approach, which follows, has allowed me to achieve 30+ pull-ups.
My first four sets I use a 45-lb plate, typically doing 12-14 reps, then 10, 8, 7.
I then switch to no weight for four additional max-rep sets.
Then I'll do four sets of both over and under hand lat-pulldowns.
I'll finish with four sets of heavy rows.