There are many ways if incubating reptile eggs. By far the easiest is to use a purpose designed reptile incubator. There are several brands to choose from, virtually all the big names offer an incubator. One of the cheapest and most popular ones is the Lucky Reptile Egg-o-bator. At first glance it 
looks a little novelty based with its egg shaped design and cheerful graphics. But it does the job for a clutch or two of small species eggs, such as geckos and snakes.
There are some options that will make incubating reptile eggs much easier. The first is the incubation kits from Hatchrite. The are available in small and large size and include everything you need to successfully incubate your eggs once you have purchased the incubator. Follow the instructions and off you go.
Other options, perhaps for more experienced breeders are Lucky Reptile Hatchboxes and of course their Hatchrite incubation medium. Hatchboxes 
are a moulded plastic box, specially designed for incubating reptile eggs. The Hatchrite medium is a ready mixed fool proof medium that is so easy to use.
The final option, perhaps solely for experienced breeders is proRep vermiculte. Tried and tested, the choice for incubating reptile eggs for many 
years. Just needs a little bit of knowledge to get the moisture correct.