I'm fairly new or returning basically from forever ago to PS battling. One thing I am often having difficulty with is predicting what moveset the enemy mom might be running. Is there any sort of guide or way to make educated guesses based on the other mins they're running?
Zneon gave some good tips, I would just like to add a few:
You can always watch some of the games others are playing! it might help to notice common team structures if you don't also have to focus on your own play; also you can see double the amount of sets in a game, since you are not looking at your own sets. Some of the current sources of games to watch are:
1. Smogon premier league(or SPL for short), a tournament where the best players compete. This tournament can be a bit different from ladder since it's conducted by people who know who their opponent will be and so they can focus more on certain builds, since they have a vague idea what the opponent could be up to, but it's still a great place to find very current builds, as the games are very competitive. Replays are here:
https://www.smogon.com/forums/threads/spl-xii-replays.3676213/
2. Official smogon tournament(or OST for short), another tournament, this one with a larger amount of players. It seems to me to be a very good source of information, as players have less idea what they are going to face, and have to prepare accordingly. This tournament also has more out there builds, so it might be easier to see some less common sets there. not sure if theres a replay thread, but some games can be found in this forum:
https://www.smogon.com/forums/forums/official-smogon-tournament.463/
3. OU team tournament. a 3v3 team tournamen(3v3 as in 3 players playing singles, not actual 3v3). Replays can be found scattered around in this thread:
https://www.smogon.com/forums/threads/overused-team-tournament-round-1.3677445/page-5#post-8745673
IMPORTANT NOTE: spectrier just got banned so the meta might differ a bit from those replays to your games, you should probably watch for new games that will come out later
4. Showdown has a feature to watch random games, which you can set the ELO of(so if you just wanna watch high or low ladder you can do that)
Another thing is that you can make scouting easier for yourself in the builder by using regenerator mons, as they can get damaged much harder and still be usable thanks to regenerator keeping them up with smart switches. good examples for this are slow brothers and pex(seriously, i have regularly seen pex intentionally take 80% hits from future sight and swap out and continue to be useful). So if you got a regenerator mon and it takes like 60% chunk to scout a set, it will not be as hard to bring out later since regenerator will bring it back up. A decently popular core I have seen lately is slowbro/glowking/corvi(first 2 have regen), and I think this core will be even better after spectrier's ban