Q: What do spices an wine have in common?
A: Keep them both out of the heat and light.
It is funny how many people keep spice racks right above their stove. That is the worst place you can keep them. Keep your spices in a cupboard that is away from the stove.
Here is another tip. Buy yourself a coffee grinder or spice grinder and grind your own spices as opposed to buying spices already ground.
When I need ground spices at work I grind whole seeds when I need them. I toast the whole spices in a dry pan over medium heat for a couple minutes (don't burn them) until their fragrance is released and then put them in the coffee or spice grinder and use them.
Remember when spices are ground they will lose some of their flavor over time. I am not saying pre-ground spices are bad but grinding them yourself when you need them is better. Or, if grinding them each time you need them is not feasible then grind in small amounts so you don't have a container sitting around for a year.
Black pepper is a good example of something that can be ground to order. Make sure you have a pepper grinder in your kitchen and only use that when you need it. That is what I use in my kitchen.
Here is another thing that is fun to experiment with. Buy some dried chilies and grind them. Whenever you see a recipe calling for cayenne or red pepper try using that ground chili mix you made as a substitute. Dried chilies have wonderful flavor.