How to say thank you "for" something?

Like if you said:

• "Thank you for my messages" 
• "Thank you for my present". 

How would you say "for" and where would it go in the sentence? And could you use the same character for a sentence like "I bought him a cake for his birthday"? Or does it depend what kind of sentence structure it is? 

I'm a bit confused :S

It was my 16th birthday today so I'd like to thank my Chinese friends for their gifts and kind wishes properly ^.^ They even wrote me my birthday cards in Chinese which I was dead excited about! ^.^ lol