The most important shortcuts

Alt+Enter: Quick fix menu when you are close to the squiggly lines.
Ctrl+Shift+R: The “Refactor This” menu
Ctrl+T: Go to functionality – just start typing (in CamelHumps you’ve got skills)

Docs

Official docs page can be found on the product page. The JetBrains .NET Tools Library contains plenty of helpful links to get to started and keep you going. It can be found at:
http://confluence.jetbrains.com/display/NETCOM/Home

Keyboard shortcuts

Shortcuts is what makes you fast. Print out the cheat sheet and put it close to your keyboard and monitor (yes, in between would be great).
R# v8 cheat sheet
R# v7 cheat sheet

Don’t want to read?

JetBrains’ own Hadi Hariri has a video on “Why ReSharper is Awesome”.
Only 12:33 minutes long. http://youtu.be/ld7ubGmxL7A

What’s next

When you are comfortable with using R#, take some time to study the settings and their layers. Create your own settings file and put it up in the cloud somewhere so you won’t loose it.
Also have a team settings file that you share with the other developers in your team.