Today was my first day of Daytrading...

I have been an investor in the markets for a long time and have prior experience with options.. However, today was the first day that I ever watched charts and tried to buy and sell in short bursts throughout the day.. I was trading 3dte ATM calls and puts on QQQ.. unfortunately I lost a little over $400 on the day but I do feel like I know the mistakes I made and hopefully learned a little from them..