While scoping out newer additions hunting new construction, having an experienced agent on your team is vital. will help you navigate the seeming infinite number of new homes today to make an offer on the one that's perfect for you.
In real estate, you can always negotiate. However, with new construction, it depends on the builder and the length of time that the home has been on the market. Developers in new additions don't like taking lower than their asking price because buyers already in the area expect new construction to be comparably priced to what they already purchased. (You'll appreciate that same courtesy if there are undeveloped lots near the home you eventually purchase!) But, depending on how far along the project is and the local market, a developer will often allow a few concessions.
Say a property has been on the market a while and the builder is deeply invested, then you have some room. The same goes for show or model homes that have been sitting for a while. However, if a home was just finished, it's unlikely you'll get a deal.
You can always ask for assistance in other ways when purchasing new construction. For example, closing costs are one way for you to save without lowering the price of the house. The same goes for amenities - ask for things appliance upgrades, a garage door opener, a fence or landscaping, or an extended home warranty. That can go the other way around, too. If upgrades are already in the contract, try to get the builder to take them out - you might be able to install them later yourself at a savings anyway.
While you should always negotiate a home warranty so problems can be fixed, it's also imperative you get a home inspection before closing. Inevitable problems can be repaired (by the builder) before you move in and larger problems identified before they become your problem. Since an inspection is relatively inexpensive, some new home buyers get an inspection after being in the home for 10 or 11 months - that way, the builder can make the repairs before a 1 year warranty expires.