Yapmayacağım şeyler ve yapmayacaklarım arasında fark nedir?

l think there is no difference.

Give me examples please,how can i use in sentence ?

Yapmayacağım - I will not do/make

Onu asla tekrar yapmayacağım. I will never do it again.

yapmayacaklarım - not sure

I think yapmayacağım şeyler (things I will not do) is easier and more used and a bit less formal than ´yapmayacaklarım´. But they mean the same. 

Sometimes it´s not easy to understand everything.
Thank you denizli  and JNQ .

I didn´t understand yapmayacaklarım.

A break down of the suffixes would be great...

Something like this:

yapacaklar = the things to be done / the things that will be done

yapacaklarım = the things-to-be-done of me

? But maybe I´m completely off here. You´re bringing me to doubt!

It must be this one:

-ecek as adjective ; something to do

http://www.turkishclass.com/turkish_lesson_345

"Yiyebileceklerimizin hepsi tükenmiş. (All what we can eat has come to an end.)" on that page is something like that I think.