Sprinkling cayenne pepper on your soup for instance will help you burn an extra 10 calories or so, but it has also been shown to suppress your appetite.
The appetite suppressing qualities of it I feel are far more beneficial then the small metabolic boost it provides.
Those who used cayenne on their previous meal in one study were found to eat 60 calories less at their next meal for example...
So for the purposes of weight loss, it would be a good idea to use as much of it as you can for the purpose of suppressing your appetite.
Aside from that, the rest of your results are going to come from you following the right structured diet and exercise plan.