Roy is a very talented character. He's packed with tons of offensive moves, but has very little range of attacks. Roy isn't my (Jeggeds) best character, so I'll just explains some good tactics to use for him.
1) Obviously one of his coolest moves is his flare blade (For those of you who don't know what that is, it's B. That's right, just B). This move charges Roy's sword to up to 50% which by the way is an instant death. When this move is totally charged it gives Roy 10% damage. Practice this move a couple of times before you play as Roy. You have to know when to stop before its fully charged if no ones going to be near you.
2) Counter. This is the move where Roy shields himself and counter attacks (B Down). As long as Roy gets hit when he flashes, he'll return the hit with a blow from his sword and take no damage. This move can even be done on the opposite side. When Roy gets hit from the back, he turns around instantly.
3) Roy's Double-Edge Dance. This move is quite cool. There are a few different types of combos. This is how it works. You hit the B button and hit left or right and Roy begins a combo. If you hit the B button at the right time after you hit it the first time, you'll do a second attack and a third, etc. you can do up to four attacks. Now, after you hit B Left or B Right the first time, you don't have to hit over for any of the other moves. In fact, if you hold the Joy Stick up, you'll do a different move for each attack. For the first attack, you have to go forward. The second you can attack upwards or forwards, and the third you can go forward, up or down. And the fourth you can go forward, up or down. Make sure you learn the timing correct on those, and make sure not to rush it when it comes to playing against your friends.
All of the other attacks are just regular.
1) The first and coolest tactic is obvious. There's nothing cooler than shooting your friend of the edge and then charging up your flare blade waiting for him to come back on.
2) The Counter. This move is really cool. When your in a big group try using it a couple of times. In the fray someone's bound to hit you during that flash. Also, when someone's running towards you they're going to attack, time it so you flash when they make contact.
3) Using the Double-Edge Dance is really cool. If your floating back to the edge try just doing the first portion of the attack. It will bring you closer to the edge to do your up-B. Just make sure you don't use it more than once, or you'll fall to an embarrassing death. Also, when your on land, I find the best way to use this is to aim upwards for all the attacks. It hits forward to, and has a wide range of motion, and it looks super-cool when you hit them with the last portion of the attack. Ka-blammo! (Say that as you send your friend off, it really brings their spirits down.
4) Remember not to smash every time. Although it does the most damage it's also quite slow. So when your close to your opponent do a couple of sword slashes instead of power attacking.
5) If your playing someone for the first time, your A Smash attack is very deceptive. When Roy charges it up it looks like he's doing it backwards, so often first time players will think that they are walking up to hit Roy from behind and Whammo! Sword smashes them!
Roy doesn't have any good air attacks. The only one he really has is in the second portion of the Double-Edge Dance if you aim up it will shoot enemies straight down, but that's very hard to do. You can always use counter, but if you fail your going to get nailed.
Also, try using your Up Smash Attack. It can do some really nice damage with Roy, especially with all his attacks being fire.
One other thing I noticed about Roy. When your doing your Up B attack to get back onto the ledge, if you tilt the control stick further to the side, you get more distance in the attack, instead of going straight up, and sometimes that can be the difference between whether or not you make it back onto the ledge.
Happy Brawling Ladies and Gents, hope these words of advice help you kick some ass!