A friend of mine just recently showed me something that would be actually really useful for artists. Warren Marshall, the senior environmental artist over at Epic games, has recently designed a program called Carapace.
Carapace is a program that makes it easy to create perspective guidelines for your digital drawings that can be used in just about any art program that you can just paste images into (though it works better when the program has workable layers so you can just make it invisible when you are done using it). Its a bit confusing when you first open it, so my suggestion is to use the f1 key as soon as you open it to see all the shortcut keys in order to use the program since it mostly is just hotkeys. Once you have everything situated all you have to do is just ctrl+c and ctrl+v into your art program and you have the guides right there ready to be used!
Seriously though for what it does guys, I could imagine it being really useful for just about anyone so I would say check this out at least.
Carapace can be found here for those who what to try it/are interested
tl;dr: click the link above for a useful perspective guides tool.