>>46111139Use enough public teams to know what style is good, who works with who, which pokemon are good in which meta, etc. You can't just build a team and expect it to be good off the bat, you need to experiment, switch out pokemon, items, etc.
Don't know if you want to play singles or doubles, but you need to make sure you know what meta you're building for too. Pokemon like Rillaboom or Landrous might be good in both metas but that doesn't mean the rest of your team will be. You need to build specifically for that meta you want to play.