Looks like you're doing pretty well already Akumakashi!

The only thing I'd add is that equipment plays a big deal in this game! I try to update equipment at lvls 25, 50, & 60 (these are the levels with a lot of cheap equipment). Its also best to only use epic or better equipment (purple, orange, or red). I use the trade broker to look for these. Epic (purple) lvl 25 equipment should be about 1000-2000 gold per piece, which is worth it. You can also get really good lvl 26 equipment in the sanctuary of sarielle if your reputation is high enough. But the price is much, much higher!

Also, Earth uses equipment with high strength and agility. (The intelligence stat is ignored for attacks).
Wind uses strength and dexterity. (Again, intelligence is ignored, while dex is used to get critical hits).
Fire uses intelligence and dexterity. (Strength is ignored).

Using equipment with high intelligence on an Earth or Air pet wastes it, and doesn't give the pet the strength for stronger attacks. Same thing using strength equipment on a fire or light pet (not enough int).