The common app provides 150 characters to describe the activity you are involved in? How will they know the magnitude of my involvement? For one of my ECs, this is what I am planning to write:
VP of PATH Club: Organized biweekly meetings,raised over $700 for AIDS Walk & presented 100+ petitions to local legislator at GA Capitol to raise awareness about trafficking.
Is this detailed enough? What are some of the things I should be keeping in my mind when writing these descriptions.
If that describes (almost) everything you did, I think it is detailed enough.
Try to cut out extra words like adverbs and adjectives. You can save characters by cutting out ands and ampersands (ampersand = &) and replacing them with comma, space when talking about separate actions you did.
Try: …AIDS Walk, presented… instead of …AIDS Walk & presented…
Good job abbreviating Georgia and 100+.
You can start by writing out everything that you did in whatever sentences come to you first, even if the result is over 150 characters. Then, cut down the length by making iterative changes to each sentence to make it shorter.