>>53542643First of all, you should understand that you will need to change teams often, so a couple of decent teams are not going to be enough.
Before playing with good teams, play random battles. And try to reach at least 1500 elo.
Use this command to learn what moves the pokemon have in randoms. Type this commands in any showdown chat and you will be the only one seeing them.
/randbats (pokemon name)
for example "/randbats ninetales" or "/randbats rillaboom"
Other useful commands
/dt (pokemon name)
/weakness (pokemon name)
Use this page
https://www.pkmn.help/ for aid with type inetractions
After getting enough skill and knowledge from playing some randoms, you can start with either VGC or smogon singles metas like OU.
Unlike
>>53544601 says, it's not such a simple difference.
In singles, matches will be longer and strategy relies on long-term planning.
In doubles, matches will be shorter and strategy revolves on a wider pool of options in the fewer turns.
Some people think that there's more skill in singles since matches are on average longer and you need to consistently make a lot of good decisions throughout a longer match, while in VGC the battle is usually decided more agressively in fewer turns. If you reach a certain level of skill in VGC, protection predictions will end up deciding many matches where the opponent is at a similar level.
However, the longer battles in singles are abhorrent to some, needing more thought and time, just for battle formats that are not even official.
This mostly applies to top rank play, in middle ranks, which is where you will likely end up, you can take it less seriously and win with fun strategies in both formats, and no format will really stand as an objectively better one.
Sample Teams:
>VGChttps://www.smogon.com/forums/threads/scarlet-violet-vgc-team-dumps.3710926/>singles OUhttps://www.smogon.com/forums/threads/sv-ou-sample-teams.3712513/ 
