My newbie-to-newbie advice would be:

1. While there's good reason why people keep suggesting certain classes, it's important to play a character you really like. CF can be frustratingly hard. Your character should be fun enough that you're willing to pick up the pieces when you get shattered twice in a session. Continually replaying levels 1-15 is no way to enjoy the game.

2. Area knowledge is golden. Being able to navigate across the map makes you much more valuable to groups. There's also tons of great stuff available if you know where to look, and especially if you can solve some quests. When you're not levelling with a group or talking at the Inn, exploring is extremely worthwhile as well as fun.

3. While the low-level recall ability is nice for exploring, it's not so nice you want to spend ages exploring at that level. You can't see the better areas this way. Recall also tends to become less reliable as your level increases. By all means, learn a few towns, get comfy with the world map, and survey some levelling areas. But then it's time to move on without the crutch.

4. Of course, exploring can get you killed. Bring a recall item - or two if there's a chance one might fail. Reading room descriptions, looking in directions, and scanning for enemies will do wonders for your life expectancy. If you're lucky enough to find an area author's name, compare that to the area list, and see if you're where you think you are - and if you have any business being there at your level.

5. The best way to avoid PK is not to be attacked in the first place. Use "where" when you enter an area. If someone in your PK range that you don't trust is there, find someplace else to be before they notice you. Periodically check "where" as well. Don't loiter in high-traffic areas (like Galadon) in any case.

6. If you're attacked, run away. Hopefully you have a recall item to use after fleeing. But either way, you need to get somewhere you won't be found. (Guilds and the Inn will only protect you if you're relatively undamaged.) Your enemy can track you by "where" if you're both in the same area - and especially if your room name is specific! Get several areas away if you can.