I bought a router 6 years ago but have lived in fear of using it! Must actually try to use it soon!
I managed to countersink a spinner assembly to the bottom of a wood panel last night. Had no idea what I was doing or what bit to use. Just looked at each bit until I found one that looked like it'd do what I wanted. Then you just adjust the height and go for it.
This (Jims) is the attitude to take to routers, never let em smell fear!

. There are some basic safety factors (eye protection, dust mask) and common sense precautions, after that it's just practice and getting a feel for how they behave. I recently sold one of my cheaper routers to a guy at work, with it he got about 20 mins of lessons from me. He keeps thanking me all the time me when he sees me at work

. Best thing to do when starting out is always practice on scrap timber first the cuts you intend to make in your work. I still do this all the time.
Mistakes I've made with routers and learnt from.
1. Never lift a router above the work when routing within a tight circular cutout, the first time I did this (yes I've managed to forget this rule several times since) the router went into insane wobble mode and ripped the ---steaming pile of meadow muffin--- out of the clean work to that point. I threw the router in a screaming fit, still spinning across the (empty of people) yard.
1.a. When you're finished routing a section always let the router come to a complete free spining stop before lifting it away from the work - see point 1.
2. Never throw a still spinning router in anger, the brief catharsis is promptly offset by greater dismay at the smashed router casing.
3. Always tighten the collet firmly enough to prevent the bit from slipping, my router table has some nice gouged channels in the metal after a bit slipped on me.
4. Check the condition of bearings on flush trim bits to make sure they are spinning nicely - they can be cleaned or replace as needed
5. Keep plunge routers clean so they plunge nice and smooth and set plunge depth carefully, i.e "plunge you sod! Oops not that far!
6. Give each and every routing job 100% of your attention and focus, don't rush it or get impatient.
Have fun