Welcome to the RP community, Dagull!
For Orc Clan RP my first recommendation is Orcs of the Red Blade. Arguably the most Orcish guild on the realm. Their 15th anniversary is coming up soon and so is the Kosh’harg, a bi-annual event which is a great opportunity to dip your toes into the Horde community. 
Also, since I haven’t seen it mentioned yet – If you haven’t already, you ought to grab the addons that facilitate RP here. The most used ones are:
- Total RP 3 (TRP3). It flags you as a roleplayer, enables you to view other characters’ written info, and lets you write your own description and any links to art etc.
- WIM (Wow Instant Messenger). Puts whispers into small separate popup windows rather than mixing them into the moving chat box. This is very convenient and lets you have several whisper conversations without constant scrolling, getting the wrong person or having to remember character names.
- Listener. Small addon that creates a discreet secondary chat box that shows only the dialogue from the person you’re targeting or mousing over. You can configure it to include or exclude certain names. A must for crowded events. It also offers some extra utility like colouring your name in chat and giving you a ping sound when someone mentions your name or targets you with an emote like /peer.