If you are self-publishing and have no interest in a more traditional approach, this post is not for you. But if you want some assistance with the process of finding a publisher, keep reading.
Selecting a publisher, one that you'll enjoy working with is like selecting a car to drive, or a college to attend, or an employer -- it requires work on your end to do the research you need.
You need to do this research up front in case they accept your submission. I almost never do that work because I almost always get rejected. Almost. And, of course, the one time I don't do that work up front is the one time I am accepted.
Not that is a big deal. Even if you want to do the research after you are accepted, most publisher deals are limited to a number of years. So if you decide to go ahead and take the deal, it won't last forever. Additionally, it is often hard to know exactly what a publisher is going to be like until you work with them, despite the research you do. In this way, selecting a publisher is like going to work for someone else, which you are in a sense. I all the jobs I've ever taken, I never know what it is like working there until I take the job and work there.
Still, you want to do some research up front. For example, you want to know which companies regularly publish in your genre and which companies accept submissions from new writers. Writer's Market is a source for some of this information. You can also search online.
From experience I can tell you, you'll want to focus on small presses. These are small publishing houses that rely on new talent to grow. Note that not all small presses are equal. I find some are really no more than one person doing most of the work. I call these place micro presses (like a microbrewery). I'm not a big fan of micro presses but like everything else there are good ones and bad ones.
Above all, check the web site Editors and Predators to stay away from know bad publishers.
You also want to talk to people who have published with the press you are thinking of using. The simple way to do this is to contact them through their author web sites. You can get a list of names by checking the publisher's category of published writers.
If you find an author has no web site, then try Facebook to see if they are active there.
So good luck with your search; hope you find what you are looking for.