Isn't really a 'levelling' system... pick a group of skills that fit roughly a 'template' you like the idea of playing (warrior, bard, mage are fairly classic genres) then select the skills you fancy to make that - or just pick a bunch of skills that look nice to you. Almost all are increased simply by using them, for more specifics have a look in the Skills section forum here, or maybe the appropriate 'class' forums on Stratics, but be aware some of their information is very out of date.

There are specific 'sweet points' where a skill will let you do most things it offers, and some good combinations of skill levels, since there is a tradeoff between the number of skill points in total you can have (if you're completely new to the game, it's 700, but slowly increases over time) and ways to use items with skill bonuses, and ways to raise the cap for a given skill (by default the top rating is 100, but there are scrolls for mose skills that can raise it as far as 120), but it's not simple, unlike 'levelling' games - use your first couple of characters to just play around with stuff and see what playstyle might suit you best, then start getting into the fine detail of tuning a template later.

The only 'naming policy' is the rather vague EA one, don't use things copyright to anyone else, or try impersonate NPCs, or use terms that others might find offensive ... it's not particularly tightly enforced, apart from the 'offensive' names, those can get reported on in-game by other players and can get you into a lot of trouble - but why start out with a name that is going to offend people in a multiplayer game anyways? Choose a suitably 'medieval' name you feel happy with, and you'll be fine. Go for a 'leet' mix of capitals and special characters, and you'll also be fine, although you will probably find the only people willing to chat with you in game are people who think 'leet' is clever, so be prepared for some pretty dull conversations