I have always tried to Learn how to make wrinkles.. And I could never ever get them right no matter what I would do.. After a few years of constantly making them I now know how so I thought I would share this incredibly easy and fun way to make wrinkles :D 

I am Going to be doing this in PHOTOSHOP as usually these days thats all I use.. You can easily do this in psp as well..

Step 1--- File New image 512 x 512 (thats my fav size these days especially for tutorials)

Step 2 - Fill with some sort of fabric Material..

Step 3 - Create a new layer above the fabric layer

Step 4 - Grab a paint brush that is set to very soft

Step 5 - Now use white and draw a line any line will do

Step 6 - Now Draw a Black line right underneath that one on the same layer

Step 7 - Now go to your layer palatte and click overlay..

Now it will look like this ----

Step 8 - Now is the Fun part.... YAY we like fun!!! Grab your smudge brush

Step 9 -- NOW SMUDGE from left to right in the same direction as your line is.. I usually go back and forth a few times..

This is what you should create---

Thats it your done...

A few notes.. --- Some fabrics you need to adjust your opacity.. in addition to smudging.. you can also do a Glausson blur in addition as well if its not as subtle as you want..

Also if you are adding a bunch of wrinkles its sometimes easier to do one layer black , then duplicate that layer and then hit CNTRL i that will make your black line white.. saving time on doing double the work.. Then i just move the black layer lower than the white layer.. shadowing should always be underneath..