Sarisio: Please, recommend a good pet build. This build must have:
1. Good tanking pet. It might be just one pet, but it must be able to endure a lot of damage and grab attention of foes.
2. Character must have half-decent ranged casting abilities.
Edit: can nature healing spell be used on pets?
The single best tanking pet is probably the core dweller in the earth mastery, since he has quite a few immunities, a skill to boost his hp and resistances, and the ability to draw aggro. Second would be the lich king in spirit since he has undead immunities and the ability to heal itself by leeching life.
The problem is that all pets become very squishy in Acts 3/4 normal, and only get good in epic/legendary thanks to the huge boosts they get there. So it would be a good idea to focus on your own ranged dps abilities first, dropping a single point in the pets you want to serve as a distraction, then get to work on being a real summoner when you get to epic difficulty.
I'd advise you to get earth/nature, focus on earth enchantment + volcanic orb and their synergies first with a few points in eruption for bosses. Then once you're satisfied with your fire spells, work on both the core dweller and the wolves so they're ready to shine when you get to epic.