A router is a very useful tool - and potentially quite dangerous. A little knowledge goes a long way toward using a router safely. Always use a sharp bit.
Dull edges make for more work.
Clamp the work securely. Fasten a piece of wood the same thickness as the workpiece to your bench. Use it to support the router and prevent wobbling, which can ruin your work. Feed the router from left to right so that the cutting edge of the bit meets the wood first. Make a series of shallow passes, gradually extending the bit.