Im gunna post a helpful strategy, one that will most definetly help you.
*btw, i just removed the numbers from the other squares, ones that dont affect the 3x3 box were looking at

*
<--- This one 
^^Were concentrating on the 3x3 Square - Middle Row, Far Right square
So, as you can see, you cant figure out what the numbers are, just by looking at the rows and columns. Yet i can guarantee you that you can fill that box

Each 3x3 box must contain all the numbers 1-9. Look at the numbers that that 3x3 box is missing.
1, 2 and 5. Check the Far left 3x3 square in that row. Theres a 2 in the top row... Go along, and it means that the 2 can only go in the middle box


Go down to bottom right 3x3 square, check the 5. Bla bla:

Aand finally, the 1. Can only go into that last place. All done

Hopefully this helps