Help with Photoshop. Discuss Help with Photoshop, on ChipTalk.net the place to go for your Poker chips and gambling tips. Read it in Custom Chips General.
Yes, check all the things that Wizard suggested. You want to work at 100% of the size of the finished product and keep the resolution on the high side (300 to 600 ppi). You might even try Illustrator instead if you're not using photos. That way you don't really have to worry as much about size and resolution. Good luck!