Always keep the soil damp and the air around the plant humid. This may be accomplished by using humdifiers which are good for humans too or by setting the plant in a gravel tray with water just below the top surface of the gravel. Inside, give it plenty of sun. This may seem strange since outside Coleus is a shade-loving plant. Remember that indoor lighting, even in a south window, is nearly always darker than the outside even in the shade.
Coleus is easy to grow from seed.
Many seed companies carry the seed. While you visit Park Seed, you may want to sign up for their free garden tip newsletter . Their website was being updated when this article was written, but go to their home page to order their catalog. It's worth the wait to receive it and often has plant species not found in any other catalog. The Burpee seed catalog also carries the wizard mix.