This is a new game, but the basic "smarts" of Melee are still present. Seeing as how you are smart enough to ask for help, you deserve to get a smart answer. LEARN MELEE, or rather, the basics of smash. There are only a few advanced techniques in Brawl (so far; it took 3 years to really get most of them down in Melee), so now, just get down the basics of smash.
Know all moves in the game: It sounds hard, but it really isn't. Okay, you don't want to know Pichu's moves, but trust me, knowing them will help, to just know, and you might learn something playing other characters about the game in general. Know how they work, and effect you, and what they do. The best thing to do is play 5 minutes with each character, doing all their moves, and seeing their usefulness. Knowing the moves is a essential part of knowing the game. Also, when those advanced techs come, learn them, even if they are only for characters you don't know how to use, to counter it, and know how it feels, works, etc. Knowing your opponent is the first step of knowing yourself.
Spacing: You might not know "truely" what this is, but I'll explain. Spacing is keeping distance between you and your opponent. Consider you are next to Shiek, and Sheik does "it's" down smash. You have to sheild to block it, and it is a bit hard to counter, unless you use a weak, quick attack. Now suppose you are a bit further back. You only have to shield a shorter time, and can attack a bit faster, due to shorter hitbox length at farther distances when a Melee move connects (hitboxes are what hit you, and the general area of the move will hit). Know the (general) hitboxes of each move (applying to the last piece of advice) is essential to winning, and knowing your opponent, and how to (quickly counter). Anyways, suppose you are a bit further, and Sheik uses "it's" down smash. You are only a bit further back-but it doesn't hit you, and you don't shield it. Now charge up a power smack while Sheik's after lag is effecting "it", and punish your foe for making a mistake. Spacing is essential for defense, and for switching "gears" from defense to offense, and even sometimes vice versa. Also, learn to dash dance (going back and forth reall fast). Look that up on smash wiki, and you're on your way. (go to the starman icon at the top of the smashboards page) Though, we still need to find out what is the deal with tripping in Brawl.
Be smart: This sounds dumb, but be smart. "Smarts" develop by playing smash a lot. Don't run into your foes. Say you are Mario, and are facing Marth, and you run straight at Marth. Marth will either punish you with his forward air, forward smash, down tilt, neutral air, dodge (and grab), or counter you move, and make you look like a fool. What you want to do IF you charge in like a person not using "smarts" would do is to fake out your opponent. Do something crazy, or in other words, mindgames (messing with your opponent's mind, so they won't know what you'll do). Don't use weak attacks that do no damage for this, but do moves people don't generally use, you generally move, or they don't see coming (preferably the later). Charge at someone smart, and have a backup strategy, or try to mindgame them.
Know your opponent, and adapt accordingly: Even if you don't know who your facing, after two minutes of facing them, you know them pretty well. Know what moves are working against you, and why. Find a sollution to get around it. Know what moves you are doing that are working, and what isn't. If a move keeps working against your opponent, be sure to let them have what they want, and punish them with it repeatidly. What doesn't work you either need to use less, mix up, not use very often, use on special occassions, or just not use at all. Also, know how you move, and how your opponent moves, know your opponent's tendecies and yours. Know what your opponent does, their style, what moves they do a lot, and find and analysis everything. Analysis everything, and your winning percentage will go WAYYY UP, but all in do time. The more you play smash, the better you get at analysising everything, and it becomes a automatic.

Also, knowing your opponent means knowing what's not working against them. Stop all unpredictable traits and attacks you are using, unless they keep working. Then, punish them with it, like they are asking for!
Play more: Sounds simple, right? Well it is, but it isn't. Play smash more. We got just under 133 hours to go until Brawl, so practice Melee all you can, without interfering TOO MUCH with work, homework, friends, and life. Play what you can. Practice against people. Get better with people. Or, do training mode. (but don't get too use to the control stick; unless you plan on customizing your controller with customized button layouts in Brawl to where the control stick is better for attack!

) Practice all of each character you use moves, and find out what is good, and what isn't. Stop using "Bad" moves, or just use them rarely, or in certain circumstances. Know what works, and use that a lot. Figure out each character you uses' move prioreties in Melee by playing them, and looking at some threads on smash 64, Melee, Brawl here on the boards.

Just know your characters like you left hand. It took me but 6 to 10 hours to "fully" conquer learning how to use Peach and Ness, but it takes a lifetime to master them. (COMPLETELY) Just practice appropriately, and win.
Have fun while learning and losing: Advanced teechs taught me not to be cocky, and to be humble, yet confident in my abilities. Learning a game that is fun is fun, right? Winning is good, but enjoy losing. By that I mean, losing is good. I SAID IT! If you lose, it means you did something wrong. There is no such thing as a perfect game of smash. If there was, someone would take no damage, and lose no stocks. TRY to find your weaknesses in victory and defeat, what you did wrong, and correct them. Don't let them get you down-it means you have work to do, and stuff to work on. If you lose, analysis what you did wrong, and correct it. Start with the big stuff and easy stuff to correct, and end with the small and harder stuff. THIS is where you will gain most of your skill, outside of common of the smarts mindsets. Losing means you need to improve. Don't get mad, sad, or angry. It just means you can be better. Don't dwell on it-fix it. If you want to be a competitve player of Brawl (you sound like you do, but there is nothing wrong with being casual about it; do what you want to do!

), you got to focus on becoming better. But enjoy your time playing smash. Winning is fun, but don't get obsessed with it. Learn to get better, and you will win. Or at least, win more often!
With time, patience, proper practice, training, sportsmanship, mindgames, good adaptation, knowledge of the game, and seeking better knowledge (from others), victory will be yours!
Since you asked for greater knowledge, you recieved it. You'd be surprised how many people are afraid to ask for information, specifically on how to get better at smash. >_> That's one step ahead of the pack! XD
Read that article from Wi-Fi Wars that Tennishilife posted a link to. It's really good, made by a Melee pro, for this special type of sitatuations you say you are in. You can learn A LOT from that!
Also, Brawl is a new game. Regardless of which character you use, it will feel "odd" at first. Don't let that bug you. We haven't" bent" the game like we have with Smash 64 and Melee.
Even at this Brawl tournament, basic "smarts", "knowledge" (learn about the basic game as much as you can), the ability to "adapt" (to a new smash game), and so on will give you a much better chance at winning. Nealdt, one of the founding fathers of the Melee tournament scene was the best player at E for All. It was no coincident a Melee pro was the best at Brawl. So the people with these basic "skills" have a MUCHHHH better chance of winning then those who don't. Just know some basic stuff at smash in general, and your chances of winning will go WAYYYYY up...unless you run into Ken, Gimpy, or Nealdt, or something!

Just try to get better, but don't get stressed about it, be patient, be open-minded, and have fun, if you seek to improve your game!
O, and the game is 1 minute, items, any stage for the GameStop tournament. Go to GameStop.com to check which GameStops are holding it, in case you don't know, by the way!
