guidance doesn't help because its the wrong kind of skill check
enhance ability -dex does help
what you need has other things; is it in sunlight or other llighting, is it in town, are there other people watching, have you already been spotted doing something iffy before
p.s, there is another spell that changes what you look like i.e, a human becomes an elf or halforc... this doesn't actually help with pickpocketing but it can help when you want to go back to the same area after without the guards grabbing you