You've played MP for eight hours? Or today for eight hours?
If you are new, we all were at one time, then PROMOTE PROMOTE PROMOTE. This multiplayer is all about promotions and equipment, you get both by grinding. As you promote the base stat for that class carries over to all characters. So get to 20 and then flip it back to 1. The more promotions and the more familiar you get with a character the more awesome you will feel playing.
Finding classes you enjoy at all levels will be the key to playing for the long haul.
eg. I favor the Legionnaire, Arcane Warrior and Silent Sister. However that is not to say those are best.
Don't fret over where you place at the end of a match btw. All gold and XP is shared.
Save any Heal on Kill (HoK) materials for crafting HoK weapon upgrades for high level uniques. The HoK materials are EXTREMELY rare.
As a new player use + constitution and + health accessories when you get them on all classes and if you get a HoK ring use that too. All items and weapons can be equipped on multiple characters at the same time.
Don't worry about hoarding potions, use them. When spending gold buy the 2000 gold chest. It gives the max return; giving items and potions. There is no way to know what you're getting or improve your chances to get something, it's all random. So I advise that you spend when you get it, I usually spend in 10k increments.
Salvage items you don't use except for purples, the chances you'll get that unique purple again or another soon are small. I do salvage doubles however.