There have been many successful marketing campaigns that have used our products. I have also seen campaigns that could have been even more successful. When choosing promotional products there are a few keys to consider:
1) A product might work because it is useful. Or at least it stays where it is easily seen and attracts some attention. Even a mouse in your hand might carry your logo.
2) Another way to make your promotional gift work is to choose something unusual, or funny, or weird. Or a product that does something unexpected. Even if this gift will not be used, it still will be remembered. Or may be even shown to everyone around to share the fun. What about a calculator that you can roll up, for example?
3) The product that you choose might also be important just as a sign of attention to the person who receives it. Add some emotion when you give it (or make it more expensive than the common set of mug, t-shirt and pen) and the person who receives it will feel distinguished. You can work this out with almost every gift except the cheapest ones. There are too many to even start giving examples.
Once you have figured out how the promotional gift you chose fits in any of the above mentioned categories, you are on the right track. Good luck!