And with all that in mind, here's an article about strategies for SSB:B (NOTE: Some tactics seems kind of cheesy)
Most are things you should already know, but a few corrections:
#1, The edge-guard-Only one character can hang onto the edge of a platform at a time, so make sure that character is yours. Smash your opponent off the side, then immediately drop off and grab the ledge.
This is technically edge-
hogging. Guarding is just using attacks to keep the opponent from actually grabbing the ledge, which in this incarnation, is much harder, since sweetspotting the ledge is much easier. Edge hogging is harder as well than in melee, because in that, when rolling from the ledge, you were still counted on the ledge during the entire roll. That is not the case now.
Ukemi is just commonly referred to as "teching."
#3, The air-steer
What it is: A way of controlling your mid-air movement to reduce the risk of being sent flailing off the stage.
How you do it: Pull the stick hard towards the stage as soon as you get smashed away from it. To do this one effectively you’ll have to keep an eye on your damage meter and be ready for the big hits, but once you’ve got used to the timing you’ll be able to drop it into your default roster of tactics without even thinking about it
Commonly referred to as DI, or directional influence. In addition, whatever direction your holding as you get hit will factor into what actual direction you go. So if you happen to be going away from an opponent when they hit you, you may well die earlier than you normally would. Obviously, the inverse is true, and what you actually want.
#1, The short-hop
When your opponent(s) are on the ground, you should always be using this.
#2, The edge-hop
What it is: A way of seriously confusing your opponent when fighting at the side of the stage.
How to do it: Drop off the stage, fall to just less than jump height from the edge, then double-jump back and grab the side. Repeat as many times as you want.
Also called ledgehopping. Usually it involves attacking at some point as well. Usually one drop, to reactivate the 1/2 second ledge invincibility, then an immediate hop up. Be careful which attacks you use. Ganondorf's up aerial A is excellent, as is Marths forward aerial A. (Some sites may call them uair and fair, to familiarize you with the terminology.) All characters have a good attack that has low lag time afterwards and decent range excellent for ledgehopping.
Additional tips
Find out which A attacks give you the least amount of lag after landing. i.e. for Ganondorf, his up aerial A will not take as long to recover from after landing, which means he's less vulnerable, whereas when landing with a down A aerial will leave you open for a much larger amount of time. If it's anything like melee, most B attacks will leave you open for excessively high amounts of time after execution.
Don't be predictable. When you kill someone, and after they come back and come towards you, don't ALWAYS roll toward them when they get close enough. They're still invincible, and you're completely vulnerable when you exit that roll. This is actually a common n00b tactic, so use it against others, but don't fall into the same habit.
Moves decrease in power and knockback if you spam them. Mix it up.
"A" moves
usually have priority over "B" moves. Don't ask why you got hit with a tiny standing jab when trying to do CFalcon's forward B, because his forward B has weeeeeak priority. Now some moves, when the hitboxes come out, like a Falcon Punch, have the best priority. But, of course, it takes time for those attacks to come out. You won't be landing much of those types in a 1v1 battle, but they're great in a 4-way battle.
That's all I've got I believe...at least for generic tips and such.