In Denver and the surrounding areas right now, there are so many different opportunities to purchase a new build. Whether it's a big builder, a small builder, or something in between there are always things to look for that are different from you average real estate transaction.
First off, you need to know who your builder is. What's their reputation? How long have they been doing it? Do they have more builds after this current one so they will stick around to fix any issues that come up. You will want assurances that once they build your house they aren't going to flee and then never be heard from again.
Secondly theres a whole different set of contracts for new construction. Builders and developers don't use the standard Colorado Real Estate contract. They do this for a number of reasons, but the biggest is to protect themselves while leaving little to protect you. This doesn't mean that you shouldn't sign/use their contracts, it just means that you really need to understand what it says and what it doesn't. You want to know what powers you have, when you can exercise them and what recourse you have if the builder doesn't follow what he's saying.
And thirdly, now is the time to be a little picky. This is the only chance you get to look at what is going in your house and be able to change anything. Are they using the correct materials so that you have a strong house that will last? Is everything where you need it to be, ie. outlets, switches, doors, internet, and cable? These are much tougher to move after your house is sealed. While it might seem painstaking go over any lists the builder can provide for the materials that are going in so you understand how your home is constructed, and make sure they stick to that.
I'm always happy to help people through their new construction. Keep in mind as well that most builders don't give discounts if you don't have a realtor, so it never hurts to have someone on board who can look out for your interests.