TRAIN. YOUR. TEAM.
Every other post on this goddamn sub is some dork going “waaa waaa [insert boss trainer here] wiped my team!!!”, and then you look inside and they’re facing a Fire type trainer with 2 Grass types, 1 Water type, a regional bird and a rodent with only HM moves, and an unevolved Ground type that hasn’t learned any Ground moves yet. And they’re all at least 4 levels below any of the opponent’s Pokemon.
Seriously, you don’t have to go hardcore and min-max every single thing, but for the love of God, at least level your damn Pokemon and bring some type advantages. Otherwise, don’t come around complaining when your precious Grovyle, Swellow, Linoone, Tentacruel, Gloom, and Sandshrew lose to Flannery for the 9th time.