Been awhile so I'll resurrect the thread with something I've been doing over the last few months that has helped me immensely.
I call it "the price of admission" to getting a drink at the water fountain. Luckily, one of the water fountains at my gym is directly next to the pull-up bars, dip station, and has a blank wall area adjacent. Whenever I go to get water (normally after every other set), I have to pay "the price of admission" before I can get a swig. "Admission" for the day is always either pull-ups, dips, or handstand pushups. When you think about how many times you get water during a workout, the numbers start to add up (10 pullups x 10 trips to the water fountain = 100 pullups in probably less than 2 minutes total). I've always been good at bodyweight exercises, but this is improving my ability to do these exercises very rapidly.
The best part is, even if you can only do one or two reps of any of these exercises, the sheer amount of practice that you get will force you to get better quickly. Try it out.