Entangling roots
Entangling roots is a very useful spell. When you cast it on an enemy it will stop them from moving and also inflict 20 damage on them over 12 seconds. If you do any other damage to them with your staff or other damage spells then there is a good chance the spell will break and they will come after you.
The main use for this spell is if you have to take on more than one enemy at a time. You can cast it on one of the monsters and concentrate on the other for a few seconds, knowing that when he joins in the fight he will already have reduced health. It's also useful to stop fleeing monsters in their tracks, allow you to run away from a fight if you get in to trouble and can also be used to start a fight when you want more time to get some Wrath spells off before he reaches you.
Again, it's best to play about with your new spells when you first get them. I've played some classes where I've ignored spells because I didn't think they were that useful at first, only to find out later on that they can come in very useful.
Rest experience
This is me returning for a second day to continue this guide and I've just spotted something else that's worth a paragraph or two. When you logout for the night make sure that you logout in an inn or a city. The reason for this is that while you are logged out in an inn or a city your character starts to gain rest experience. You will continue to gain rest XP until you log back in again. You also gain rest XP if you logout elsewhere but the rate at which you gain rest XP is greatly reduced.
Rest XP is a bonus XP system that means for a period of time you will receive double the normal amount of combat XP. Take a look at the XP bar in the screenshot above. Just to the right of the end of the blue bar you will see a marker. This marker shows you how much rest XP you have stored up. From now on and until you reach that bar you will get double XP for every kill, meaning it will take less kills for you to reach the next level.
You can save up to a maximum of about one and a half levels worth of rest XP. However, this would take about ten days to accumulate and I doubt very much that you can stay away for that long. It is a nice bonus to get when you return from a holiday though. It also comes in very handy later on, when you need more and more XP for each level.