Tips for reading patterns...
First things first, you need to learn how to know what a pattern looks like. To do that, save your replays, then watch how your opponents fight. Watching them you'll notice how there's certain behaviors the opponents repeat, like maybe they always go in for a fair while landing, or they try to edgeguard you by ledgedropping a fair, or at low %s they're a tad bit too grab-happy to try and get a nice combo off of you, etc. Once you can see the pattern behind their gameplay approach, you can devise a countermeasure.
Sure, in this particular scenario it's already after the match and you've already lost, but if you don't even know how to properly punish someone, we're going to take it slow, and this is the right step to take here. Just watch replays, notice how your opponents kept punishing you, and think about how you should've done things differently. Did they shorthop and approach with fair? If so, would firing a projectile when they jump be humanly possible for you? What about when they're coming down from a shorthop, are they throwing out an aerial only when they're landing? If so, is your character fast enough to get in and intercept them as soon as you see them jumping, before they throw out their aerial? Also, what about when you're recovering, do they keep somehow edgeguarding you perfectly? If so, are you recovering the same way over and over, and so letting them know that they can do the same edgeguard over and over again?
Essentially, your first step is to take it easy, and in a less hectic setting, see if you can tell what your opponent's patterns were. The more videos of yourself you watch, the easier it'll start becoming to tell when your opponent is "doing the same thing over and over again." After you get enough experience watching your replays, at some point you'll start noticing them mid-match. At first, chances are that you'll either camp the opponent trying to figure out a way to punish them (and lose stage positioning in the process), or you'll go in trying different things to see what works (gaining percentage/losing stocks in the process). With enough attempts over many matches, you'll start to learn what your character can punish, with what it can punish, and what it can't punish at all. At that point, you'll have incorporated into your playstyle how to bait-and-punish, which believe it or not, is something EXTREMELY important needed to get past one of the major player skill plateaus you'll encounter, and which many players actually don't quite know how to do and/or can't consciously do.
As far as edgeguarding, it's basically the same thing, except you'll have to add into the mix player experience. The more players you play against, the more varied recoveries you'll see, and the more opportunities you'll have to find out what most people tend to do to recover. At some point, you may notice that the players around you tend to recover from high up moreso than recovering horizontally or from below the stage, and from then on you just incorporate bait-and-punish tactics; read where you think they'll go, and react accordingly.
