Does anyone have any suggestions for what I could do this summer to help my college application look better? I am a junior, going into my senior year.
The good things I have so far is I created a GSA (gay straight alliance) at my school, and we have leadership meetings to help change the environment around school. I am in NHS (national honors society). For my senior year I am creating a computer science club, and the plan is to meet hi weekly and be able to take the AP computer science test (my school doesn’t have any computer science courses).
So what do you think I should do this summer to help me look better? I was thinking about going to a college summer program, but i think I missed out on the deadlines for the good ones. Should I just keep volunteering, or should I try to maybe get an internship? Any suggestions will help! 
Volunteering is great, as is a job. You don’t need expensive summer courses to have a good application, but they aren’t a bad thing either. If you are into computer science, there must be umpteen things you can do to show your interest in computers. Maybe volunteer with elderly people and help,them navigate the Internet. Or have you created any programs? I think the idea of an AP comp science club is a good one and that might be a good thing to build in and emphasize in your app. Meanwhile, getting a job is definitly worthwhile.
Be careful with adding significant activities. Ad coms are very alert to resume padding, and can spot it in a nano-second. Your best bet would be to focus on greater involvement/increasing the impact of your current ECs.
Focus on things that you’ve already had a lot of involvement in. Ex: see if you can get a comp sci internship or maybe do dual enrollment for comp sci. I would really recommend taking a cc class over the summer if you have the time or maybe even getting a job (if you can handle both).