What are some ways to improve my push-ups before bootcamp?

Form & repetition: Learn and develop good form. On toes, back straight, head straight, even with back. Hands flat, out from and even with shoulders. Practice lowering until chest almost touches floor and raising until elbows straight. Do slowly to develop form and strength. Then practice going faster, but maintaining form, to get repetitions. Practice in am and again in pm. Start slowly and build. You will improve.