With a standard tournament coming up this sunday, for many of you, this friday; there are certain things I must do in order to prepare for this standard tournament. Also, keep in mind that this is from an FNM-level perspective.
Know the Metagame
Many people show up to events like Friday Night Magic with "netdecks"- decks straight off the internet, card-for-card. The reason why the deck may not have done particularly well at your fnm is because it may not be geared up to your local metagame. To prepare to take on the metagame, you must revise your main deck to be suitable for game one against the most common deck(s).
Bring a friend
Friends will always be there to support you as well as help you. During the Alara Reborn prerelease, I brought a friend (we'll call him John). John finished his round early and I was still in for a long game, still in game one. We were both really hungry, and there was a pizza shop about a block away. I told John my plan to concede the match and get food with him. Being the amazing friend John is, he offered to bring me back pizza, so I was able to play the rest of the match, and continued on to win games 1 and 2.
Test Your Deck
Keep testing your deck against decks in the metagame. Good sources for testing are usually found on computers running windows (sorry fellow mac users). Magic: the gathering online is the most famous of all programs, allowing you to play the best form of paper magic, but for a big price. Magic Workstation allows you to test your decks for free against the AI or other players. communication is decent, and it has every card ever printed on it.
Practice makes perfect
If you are planning on going to an important limited event, for example a prerelease or launch party; there are many website utilities besides Magic: the Gathering Online that allow you to enter a simulated draft. Ccgdecks allows you to draft with other people or bots, for free. It also allows you to simulte sealed pools. Tcgplayer allows you to draft for free a few times a day, and if you have an account, you may draft an unlimited amount of times!