I know that the first official day of (early action) apps is Sept. 1, but when do you recommend I actually send in my application for early action?
The earlier the better. Sending applications early shows that you really want to get in, you’re a responsible applicant, and there’s more time to account for errors if any come up with the application submission. It’s better to encounter a problem a week before the deadline rather than the night before.
Send it in as soon as possible. If you send it in during the early period, you’ll be accepted quicker because they only look at your GPA and ACT score, and if you meet the minimum (which can change every year), you’re in. If you don’t meet the minimum, then they look at your essays and complete application.
If you get in earlier, you can apply for housing earlier, which means you’re ranked higher for your preferred housing area - which can be a really big deal for some. Also, it’ll help you stay up to date on scholarship deadlines.