Well... HS diploma, within the weight standards, no legal or financial troubles. Speak to a recruiter, take the ASVAB, be one of the best of the best your recruiter meets, get through MEPS with a clean bill of health... Get a ship date, go to boot camp and welcome to the CG!
Seems simple and in a way it is. However, like you have discovered, the CG is the toughest of all the branches to get into. That is because it is the smallest and can afford to be the pickiest. If you have any other questions, let us know.