Save replays is all I can tell you. If I play really good players in FG, I come back to this site to see if I can find them in hopes that I'll be able to have more matches with them and get some feedback. As for safety, there are a number of characters I feel can only go in safely and not worry so much about getting hit or taking lesser damage than the amount they're giving. I remember in previous Smash games, I felt like I could really punish people and play safe. Now I feel like if I try to apply shield pressure, I get grabbed or attacked out of it. I would imagine online friendlies and in-person matches are a lot more fun and interesting than the ones on FG. I mean, the good players I've fought on FG really get in and don't play around. Then there are those that sit at the edge and wait for you to do something. I'll give you an example.
I was trying Ganondorf out in FG because at my friends house, I had a ton of fun using him, so when I was at home on my 3DS, I fought a Kirby that would stay at the edge and try to inhale me off the stage. The first stock, he made that attempt, I jumped out and footstooled him and got back to the stage. As he was jumping back up, I spiked him. On his second stock, he went to the edge again, tried the same BS, and I figured I'd just try to get behind him and Flame Choke him off the stage and win that way. It didn't happen. I managed to win, but the match itself was boring so I left after the first match. I joined someone else's room, they attempted the same BS and I managed to win again. I figured at that point, I'd just use Ness for the rest of the night to avoid that.
I can't say if a Kirby main would attempt that at a tourney. Even if they did, I don't use Ganondorf, and against a Kirby main, I most likely wouldn't after having the knowledge that my opponent is going to use him. As for good players that you can go against, the one I fought, I didn't feel any pressure mentally. In the game, my opponent applied pressure, but I wasn't freaking out. It was odd. Not sure if it's just me getting used to matches now because of FG or not.