Right, to add friends, make them add you as their sponser when they first join. The best help I can give on trading, is to sell a card as private for 50 clints and have the other person do the same.
The Urban Rivals team is made by lovers of all kind of Collectibles Cards Games and Trading Cards Games like: Magic the Gathering, Dominion, Vampire, Yu-Gi-Oh!, Pokemon, Wakfu TCG, Assassin Creed Recollection, Shadow Era, Kard Kombat and Might & Magic Duel of Champions.