Initially, most of what you concentrate on when you first start to play games World of Warcraft will undoubtedly be the leveling process. When you enter the realm (unless you happen to be a Death Knight), you'll start off at level 1, and will begin the climb to level 80 very quickly.
In the World of Warcraft, leveling up requires you to gain experience, which you can do in two main ways which are:
1. Completing quests
2. Killing non player characters
Both of these actions will give you experience points, and once you hit a certain number of experience points - you'll gain a level! With every level you'll find that your character grows more powerful in many ways ranging from statistics to spells and talents.
Also, you'll be able to wear better equipment, which is going to help you out a lot too!
Many new players find that the first few levels come very quickly, but as time goes by it slowly but surely gets harder and harder to level. While it is fairly normal to gain the first 10 levels in a matter of hours, some of the higher levels could even take days.
Gradually, you'll get into the groove of things though, and find that leveling up isn't really as hard as it might first appear to be. By going through the readily available quests, you'll find that you gain a lot of experience - which is why one of the most effective ways of leveling is to keep doing as many quests as you can find.
Every couple of levels of free games that you do gain, you need to be sure to train up your skills and spells so that you're able to fight higher level monsters. Also, be sure not to neglect your equipment or you'll face a lot of difficulties later on too!
End of the day, leveling in World of Warcraft is a fairly natural experience, and now that you know the basics you shouldn't have too many problems with the entire process. Just keep at it and in no time at all you'll find yourself a strong level 80 and ready to take on the world's toughest monsters.