Family History: any suggestions?

I'm trying to do some family history. I'm a beginner and I'm pretty sure I could use any suggestions anyone has out there!

A lot of my family history work has been done straight back as far as we can, so I'm trying to work laterally, as they call it.

Right now I'm working on some great, etc grandma's brother - Mads Sorensen. Born September 4th, 1829 in Denmark. All his work is done except being sealed to his wife. We have no record (yet) of his wife. So my effort today was spent trying to find his wife. I don't know her name, her birthdate, her parents. So basically I searched for ____(blank)__ Sorensen, whose spouse is Mads Sorensen (since that's all the info I had).

255 people came up. So I looked through all the Mrs. Sorensen's and clicked on the ones born anywhere from 1820-1860. The majority of them where already sealed to a Mads Sorensen with a different birthdate.

If he's not connected to a wife, yet I'm searching for a wife who's husband is ("connected to") Mads Sorensen, that probably wouldn't workout right? How am I suppose to search for someone I don't have any info on?

How do you find people laterally who you don't know who they are? Census records? (yikes) How is family history easy?