Don’t overlook condos. Investors have been snapping up condominiums to rent out amid the development boom, creating opportunities for high-end renters. A big concentration of investors can mean a surge in rentals when the building starts to close, said Marc Schaeffer, a real estate agent at Kleier Residential. “You have to catch the timing right,” said Mr. Schaeffer, who noticed a rise in rental listings at Carnegie Park, an amenity-laden condominium at Third and East 94th Street, and was able to get clients a $150-a-month discount on a two-year lease for a two-bedroom. Instead of paying $5,800 a month, with an expected increase of 2 percent to 5 percent the following year, his clients are paying $5,650 a month. “We accomplished this by pitching our offer to similar listings in the same building and letting the owners’ broker know we were submitting the same offer to other apartments,” he said. “This worked because we were dealing with three different competing landlords.”

End your lease in the summer. In general, rental demand picks up from May through August, when school is out, college grads move to the city and the weather is better. So when Elisabeth Polanco, a kindergarten teacher in Washington Heights, wanted to move to the city from Rockland County, N.Y., this spring, Sherry Mazzocchi, an agent at Citi Habitats, knew what to do. By asking for a 15-month lease instead of the typical yearlong term, she reduced the rent on a three-bedroom walk-up to $2,225 a month from $2,450, with an April 4 move-in date, saving her client $3,375 over the course of the lease.

Move in the dead of winter. Knowing it is harder for landlords to fill vacancies during the winter, when rental activity tends to wane, Jordan Kramer, an agent at Compass, helped Sasha Sherman and Ben Cohen knock $400 a month off a newly renovated East Village three-bedroom walk-up that was asking $6,000 in December 2014, for $4,800 in savings. The roommates, who were sharing with a third friend, initially offered $5,800 a month with a Feb. 1 move-in date. Aware that there were no other offers on the table, Mr. Kramer recommended his clients ask for another $200 off if they bumped their move up to Jan. 15. The landlord agreed. As a result, said Mr. Sherman, the sales manager for BOLD Organics, a frozen Italian foods brand based in Harlem, “we got an incredible deal on a beautiful apartment.”

Pay your rent upfront. For those with the means to do so, paying at least six months of rent in advance can net you a discount. Last year, Jesse Klein, a salesman at Platinum Properties, was working with a college graduate and the graduate’s mother, with a budget of $2,700 a month. After touring a number of apartments, they visited an open house for a $2,750-a-month alcove studio in the East Village, where they found other prospective renters lined up outside to see it. “My client’s mother literally took out her checkbook and said to the owner’s broker, ‘I will write a check now for six months’ rent if you can knock it down by $100 a month,’ ” Mr. Klein said. “I was like, ‘All right, this woman means business.’ ” While not every landlord would entertain such a request, Mr. Klein said, the owner’s broker jumped on the phone and got the landlord’s consent.

Be creative. A landlord who won’t budge on the rent may be willing to waive gym memberships, parking or other costs associated with a rental. In January, Kevin Djungu Sungu, an agent at Citi Habitats, helped a client secure a $2,550-a-month one-bedroom at a new rental building in Harlem that was originally listed for $2,650. In addition to paying the broker fee and offering a free month’s rent, the landlord agreed to increase free storage to one year from six months.

Be respectful. “I think people get the impression that they have to be some kind of animal going in and negotiating,” said Adam Frisch, a principal of Sierra Residential, a brokerage firm that specializes in landlord representation. “What doesn’t work is to call up and say, ‘Listen, you have to send me a lower increase or I’m going to sue you.’ Or ‘You’re not taking the garbage out enough; I’m going to get the city to give you a violation.’ ” His advice: Stick to the facts. Remind your landlord with a note that explains that you are a tenant in good standing and always pay your rent on time. If you point this out and ask politely for a reasonable rent reduction, Mr. Frisch said, “often the answer will be yes.”