When you log on to bNet there are a few things you need to know, before entering the pointless playing in ladder. If you are pretty new to WC3 and don't know where to start make a few games, see wich race you like the most and take the race that fits you best. Of course they are players like Moon, Remind, Check, apm70 that use more than one race, but it takes a lot more time to study those Match-Ups and strategies and the counters againts them. Now let's begin with the interesting part. Let's say you have choosen to play with Night Elves*:)*. When you start playing some ladder games, you will win some and lose some. Why? Because they are many strategies that you haven't encountered yet. What you have to do when facing a new strategy is to remember it. I will ask you really easy question now - what is better:

1. Make 50 games and don't remember the mistakes you made and make them again.
2. Make like 20-30 games, but remember what you did wrong and try to understand it.

Answer #2 looks better right? Study your opponent and the strategy you lost to. Yes it's very important to study your mistakes and watching the replays will also help you understand why you've lost. You have to know that some strategies are better than others, and some are easier to play while others are harder. So when you start playing some strategy and you lose to someone, check your mistakes. Change something in your style and see how it goes.