Dark nights and dark adaptation, as well as some experience and persistance are essential to see M33 (and other faint DSOs). I'm relatively new in astronomy, having started just a few months ago. After several nights attempting I could finally see M33 last weekend. It was a "Gotcha!" moment, and I was very happy.
I was impressed with what I saw. It was very faint and fuzzy, however I could discern some heterogeneous structure and the impression of spiral arms. It's a hard object to see, but the challenge was well worth it. The night was relatively good. Bortle 4, no clouds or moon, but a lot of humidity (around 60-70%), therefore lots of skyglow. I live in the Southern hemisphere, around 22 degrees, so M33 is never more than 36 degrees in the sky, unfortunately.
Next night, same conditions, but my parents stay wake until very late and keep the light up, so I'm not as dark adapted (still relatively so). I try to find M33 all night but can't. When I finally get to it, I see only a small smudge, the galaxy core an nothing more. Proper dark adaptation is essential for this DSO.