Email the hotel and ask for a lower rate. Do not email the hotel's booking service, as these people have no authority to negotiate rates. Email the hotel's manager or other higher personnel directly. Ask if the hotel has any specials or if the hotel gives discounts to AAA members or AARP members or to any other group you are associated with.
Be flexible in your booking times. Often a hotel will be willing to negotiate a better price online for a particular day. If you are able to arrange your schedule for that day then you can take advantage of the deal. Keep in mind that hotels may be more inclined to negotiate price for a weekday stay rather than over a weekend, when hotels are typically more fully booked.
Search online for smaller hotels, B&Bs, and other lodgings that are not typically the first choice of travelers who are often more concerned with name recognition than with cost. Contact these alternate choices for accommodations and ask for their best rate. Often you can negotiate an excellent deal and have a more homey and relaxed stay in the bargain.
Ask the manager for an upgrade if the hotel is unwilling to negotiate on prices. You may be able to get a suite for the price of a regular room or you may be able to get breakfast thrown in for free or some other perk which will make your stay less costly.
Plan your visit for times when the hotel is not typically booked. Do not try to negotiate a good rate if there is a convention in town or at the height of the tourist season, when the hotel can sell all of its rooms for full price.
Compare prices on various travel websites. These online companies typically book unsold rooms at a considerable discount off the hotel's posted prices. If you have some flexibility in your location, booking just before your trip may get you a favorable last-minute discount.