Start working on your applications at least a couple months before they are due. This will ensure you have enough time to proofread everything!
There is a section that asks for brief descriptions of extracurricular activities; use this to your advantage! Talk about what change you implemented, not what every single member of that activity did. Colleges typically want to see how you shaped your community and vice versa, so think about what you got out of an activity and mention the experiences that changed you.
There will be an essay that you send to every school (unless a school does not require it); this is the time to let your personality shine. Many applicants also choose to start with a metaphor to introduce their essay, and many make jokes and puns. Do whatever helps you come across as yourself!
I would recommend using the "choose your own" prompt for that main essay to avoid any reviewers bumping your application down because you did not follow a prompt.
You don't need to be a walking thesaurus to get into college. Write as you normally would, and make sure you understand all the words you used. I have received emails where the sender obviously looked a synonym up online, and that synonym did not fit the context of the email.
There is an "awards" section; use this to show off! List your honors in order of importance to you, ensuring you put less grandiose or less recent awards honors further down.
If you have not participated in 10 activities or won 5 awards, that is okay! In fact, good for you for not spreading yourself too thin. Just leave any remaining sections blank.
"Optional" essays are not typically actually optional; if you have the time, write all of the essays that apply to you. This helps schools see that you are interested in them!
Guidance counselors are there to review your essays, not write them! Feedback is often more productive as a conversation; point out areas that you have questions about (e.g. Is word choice A or B easier to read?) and, if you can, schedule an appointment to talk with your counselor about what you wrote.
At the end of the day, college is not about where you go, but what you do while you’re there. Try not to stress out about not getting into a given school; it is hard to put yourself out there like the application process requires you to, so even applying is a huge accomplishment.