R.J.
Strength increases as you do more, but adding in different kinds of exercises will help, both in speeding things up, and by strengthening different sets of muscles. It's a circle... the more muscles you're using, the faster you get stronger
Pullups
Pushups
Climb ladders
Climb ropes
Arm circles (small and large)
Tray carrying (think restaurants)
Heavy backpacks (fill 2 liter bottles with water)
Backwards pushups (off the edge of a couch)
Lizard walking (think kids goofing off, or no wheelchair)
Low crawling (army guys)
Crawling (yep, just like a baby)
Handstands (against a door if your balance isn't good, yet)
Handstand pushups
Dance
Sex (quite a few positions)
Bucket carrying
Kid carrying
Tree climbing
Swimming
Massage giving
etc.