After you have that all-important pre-approval, then the next step is to think about what is essential to you in a home.
Depending on your down payment percentage, you can consider either a co-op or condo. With rare exceptions (and they do exist) most co-ops require at least a 20% down payment. But many people can buy a condo for 10% or even 5% down.
Also, if you absolutely must have the ability to rent the apartment out, then you can only consider condos. Otherwise co-ops provide more square footage for the money and provide certain other advantages over condos. Fewer people can qualify to own a co-op, so that's one reason their prices are lower.
I often represent buyers and would be happy to help you. One important service your own agent can provide you is to help you research the history, surroundings and financial stability of the building before you make an offer on an apartment.
Remember too that the agent you meet at an open house is working for the seller, so be very careful what you say! But any licensed agent can represent YOU as a buyer, and put together an efficient tour of apartments that meet your criteria, and negotiate hard for your best interests, and keep aggressive seller's agents at bay. In NYC agents share commissions so you don't have to worry about that part. as a buyer.
One last thing: If there is a dog in your life, be sure every apartment you visit is in a dog-friendly building. Cats are more generally accepted but there are so no-cats buildings as well.
Licensed Real Estate Salesperson
New York, NY