Q: how to increase number of pushups

A: The simplest way is to simply keep doing pushups a lot. You can do them 2-3 times per day to failure, which means do as many in a row as you possibly can. Your pushup strength will build up real fast. You could do weight training to increase chest and tricep strength as well, primarily through the bench press exercise, but really it won't give you significantly better results than just doing pushups.

The other big thing is to lose weight if you're overweight. This can make a huge difference if you're significantly overweight and can lose 30 pounds or more. Read my fat-loss article and follow its directions to learn how to lose weight most effectively. But only do this if you're truly overweight.