>>17573280Luckily for you, pokemon probably has the easiest competitive scene to get into. The first thing you will want to do is get a good feel for type match ups. Pic related, a handy reference.
Try to get a few pokemon with different weaknesses, and give them moves that can help deal with what they are weak to. Also, Ice and Rock type moves are great, while Ice and Rock type pokemon are usually bad.
>>17578504Smogon's competitive play is also based entirely on singles battles. Official tournaments, as well as most unofficial tournaments, use double battles. It is a good idea to start off with singles to learn the basics, but not everything carries over well.