1. Shop around
With chains, it pays to be loyal: The best deals are usually found on the hotel's website. But for boutique options, the biggest savings are often offered by online travel agencies (OTAs), like Orbitz. A recommended first stop: kayak.com. The site scours all the OTAs and lists their best rates side by side.
2. Earn points
In May, boutique hotels got their first-ever reward program, Stash Hotel Rewards (stashrewards.com). Members earn points at 81 locations across North America. Stay three nights at Hotel Fifty, in Portland, Ore., for instance, and get a fourth free (hotelfifty.com, from $98).
3. Earn cash
The second entry in the boutique rewards race comes from Epoque Hotels, a Miami-based group of 350 properties around the world. Like Stash, Club Epoque (epoquehotels.com) is free to join, but instead of earning free nights, members get 6 percent cash back toward their next Epoque reservation.
4. Save in Asia
A regional branch of priceline.com, the 10-year-old booking site agoda.com focuses on boutique hotels in Asia and the Pacific Rim and typically offers the best rates in those regions. It also has extensive photo galleries that cover each hotel—more pictures, even, than you'll find on the hotels' own sites.