The Step by Step books are normally good. I don't think there's one out for SSRS 2012 yet but since general report development is not radically different in 2008 you could get the step by step for that here. A good idea would be to work through the tutorials I linked to before using the microsoft examples to get you a good grounding. Then use some actual business data that will mean something to you. This will help you see how it all comes together in the real world.

Other thoughts, hmmmmmm

DO

Write decent SQL/MDX that is well optimised. No matter how nice your report looks, if it's running on a slow query your users won't appreciate it. In my opinion, in SSRS the query is the most important thing to get right. This can also include having correct indexes etc. or if it's MDX, good dimension design etc.

DON'T

Overload your report with needless images/sub-reports/charts/etc.

Remember you are displaying information for people to consume. Keep it simple and clear. Also remember the report has to render so having a lot of superfluous things on it can slow it down.

DO

Use Shared Datasets.

For example, if you have a parameter that is going to be reused in the same way across more than one report then use a shared dataset. It cuts down on development time and maintainence time.

DON'T

Use Shared Datasets if they are only used on one report. This is just silly and I've seen it done by other developers. They should be tortured.

I could go on all evening but it's dinner time and I'm hungry. Good luck 🙂