I saw this sentence tunci had posted 

" Senin böyle bir şey yapabileceğini hiç düşünmemiştim."

Can someone explain to me why "miştim" is at the end of the sentence and not "mişim", as well as more examples and when to use which.

Here is my understanding:

miştim is like I hadn´t - past perfect

mişim is like I supposedly - inferential past - this could mean either second hand information or uncertainty

yürümüştüm

- I had walked

anlamışım

- I thought I understood

- someone said I understood

- I apparently understood

http://www.turkishlanguage.co.uk/pasttense.htm