Is there one cuz evry time I go to make on I mess it up :C

You can search here the bicep texture's template that you want, and draw the armband.

This is the triceps template. You can get them by going to: Shop -> Textures -> Template

Make the strip vertical with the "in front back and out" on the templates ^

Use the interwebz pictures as reference.

That's the part I mess up on ...
I cant do the vertical line part that is what I mean...............................

Are you using photoshop or what?

Paint.net

There is your problem, sir. I would get the free program, gimp, and look up some tuts. It's much easier to make things the way you want them.

Link, paint.net is free, and is like an easier version of gimp, lol12w, I made our sig and avatar using paint.net(and some other programs), its extremely simple to make a straight line, pm me if you want help.

If you want a good armband, I would use gimp. Not saying you can't use paint, but it won't give you more than very simple projects and I am not very accustomed to the tools, so no help there. If you start using gimp and want help, you can shoot me a pm aswell. I have taken classes for this sort of thing.