I was asking almost exactly the same question a few weeks ago; I ended up at 3rd in my tournament! Here's a link to the thread.
My reccomedations: It's going to be a bit difficult to come to a good understanding of an opening. I'd reccomend remembering the main lines, and if you have time why each move in that line is a decent choice. Also try to find what the underlying theme or goal is behind each opening you play. For example, in the sicilian, I like to think of it as "whomever gets there attack first wins first". Last but not least, brush up on your tactics; this is key! Chess is 90% tactics, and 10% strategy! (Or was it 99% tactics, and 1% strategy? Either way tactics study is the way to go!) Review mating patterns you often come across in the endgame.
Best of luck,
photray94
I have my first tournament coming up and i want to prepare for it. any help will be greatly appreciated. The tournament is on the 25th this month and is G/45 TC. Im working on sicilan against e4. and mainly doing e4 openings as white. Im not sure i want to try kings gambit or the piano against e5 but im liking smith-morra against c5.