If you want an iguana to come share your home with you, you'll have to first demonstrate to the iguana that you'd be a good patron. Explain to the desired iguana that you've given careful thought to the following issues, and it will be much more likely to accept your invitation:
**Room to grow**
Iguanas get really big. That little 15-gallon glass tank you bring her home in is going to last about a year, then she's going to need a much bigger house. And then she'll outgrow that, and it'll be time for an even bigger house.... Eventually, you'll probably need to consider giving her a whole room! Make sure that you plan out your iguana's future housing needs before you get an iguana!
**Proper full-spectrum lighting**
Iguanas need full-spectrum lighting, especially when they're young. Without it, they will suffer from severe calcium-deficiency problems that will almost certainly prove fatal. It is absolutely essential that you provide your iguana with full-spectrum light, such as from a full-spectrum fluorescent bulb. These bulbs can be rather expensive, but without them, she will suffer miserably, and won't make it past the age of two years.
**Underbelly heating**
Iguanas need underbelly heating in order to digest their food properly. The best thing is a heating pad (sold in pet and reptile stores) affixed to the underside of her floor. Electric "hot rocks" are not recommended due to the high potential for thermal burns.