Some tips for beginners:
As sengsong mentioned play pvp, pve games
Copper mountain game, a pve game run frequently at low lvls below lvl 10. Quicker to start, less waiting time and more chance for good sign amount.
How to play: open "subscription" in lower panel (right most icon), go to PVE games tab, select Copper Mountain and Click on Join. There is a cooldown timer after each game.
What to do in Copper Mountain: KiLL the Mobs! and sword boss at the end of the dungeon (pretty easy for lower levels).
How to buy pet young exp potions and food with signs:
"My wallet" will show how many green signs you have collected .. Click on green sign then "USE". A 2nd window will open, browse the 5th tab for pet food and exp potions.
Pet's satiety runs faster if its is running with you. So, if you are not in action putting the pet in bag minimizes the need of food.
Check mob loots for items. They drop randomly and better than nothing (Blue items better than green ones)