Welcome to the Course and Best of Luck. Good job! Homework #1 Done!
I wouldn't say it's bad that you ain't playing long sessions. You can always make some smaller sessions and more of them. Depends really what suits the best for you, if you are busy with other work and stuff then sure, this way works also fine.
With poker it's practically the same as with driving, why it's not allowed to drive with car then you drink? Because you can more easier lose concentration and the same goes for poker. You will most likely not concentrate enough and make a lot mistakes. Of course you can play drunk when you just want to have fun but when you want to take it more seriously then I would rather recommend not drinking beer during poker.
But obviously it may also vary from people to people, some may even still keep their A-game even with few beers.
What about tilt? Do you adjust something against it? For example:
Easiest way to fight against tilt is to set up stop-loss technique. Which means if you for example have lost more than 3BIs for a session then you just stop the session for some time. The BI amount is set up from your own results. Some may put it higher, some lower. Also after the stop you can spend some time with evaluation part to become better.
Tight style is usually called playing selected hands. Like following the Starting Hand Chart. Aggressive should be also pretty clear that already the word says how you should be playing. But the problem playing aggressively is that you have to watch that you don't play too aggressive. Find good spots, find good targets. About The tight-aggressive strategy you can read in this article: "What is the Big Stack Strategy?"
Hopefully you will enjoy the Course.