Every games store needs some essential items. These are really quite simple:
1. Product availability: You need to actually have your shelves stocked or have a very simple ordering system. It should not require a ton of effort by the customer to do this.
2. Product knowledge: Know what the hell you are talking about. At least go onto the internet and look it up. Not hard at all. It's even better when you play the games
3. Gaming space: It can be created if one tries hard enough. If not now, plan to expand in the future. Gamers often need a dedicated space to play their games. It also builds a community in which more people will play.
4. Specials: There should be some level of special, discount, deal, package. Try to make it unique and interesting. Of course, profits are profits, but gamers really appreciate a deal.