If some of the impulse items seem to be the type that grow legs, display them within a glass cabinet or shadow box, out of harm's way but very visible. One locksmith shop that I visited for this article sells garage door remotes. Samples are placed in a shadow box on the wall behind the counter. Several signs throughout the store promote that this locksmith store will not only sell you a garage remote, but also where possible, they will program the remote to yours.
Why not sell batteries for garage remotes and vehicle remotes? There are companies that have test equipment and replacement batteries all on one standalone rack.
One reoccurring theme seems to be keeping all similar items together. This seems to be most common for painted keys and key accessories. This way the customer can make the decision without having to move around much.
Just about everyone is looking for a deal. One possibility is to create deal areas within your customer area. This could include something very small such as a basket attached to or on the front counter containing old, new and used padlocks with a sign indicating all of the padlocks are only $$$. Within one such basket, I found several heavy duty padlocks that if they were new and still in their original packaging, they would sell for many times this asking price.
Most locksmiths have locks and other types of door hardware that has been around forever. Why not setup a small table in the customer area and place a sign, “Everything on this table is $$$?” Include at least a few name brand items to draw the customer's attention to the table.
An important aspect of a store's setup is to have the easy-to-identify and read pricing. If your customer has to look or ask for pricing, it normally breaks the flow of the impulse sale.
Track the sales of the different types of item on display. If a particular type of item sells well, try displaying additional products that are similar. If a particular item does not sell well, try discounting the price to see if sales will improve.
Setting up your “customer area” can be accomplished over time. If it is accomplished gradually, the expense is absorbed with the increased profits.