What you're trying to do isn't very difficult, but it sounds like you don't have much PS experience. Just using basic PS is a process in itself, and can be daunting, but if you want to learn you should be able to manage this. At least, cutting out non-white cabinetry from a white-ish background. I'm not sure what you're trying to do with the mirror, hide what it's reflecting?
The best way for both of these is of course, proper photography. Using lighting makes it easy to blast out those wrinkles. Likewise, the best way to deal with mirrors is the make sure they're not reflecting something you don't like when you take the photo.
But as far as Photoshop you have two basic options: Either over-expose the white-ish background all the way to white, or simply cut out the background and replace it with a white (or any color) background. It's outside the scope of this forum to walk you through this process, but just go onto youtube and search for "white background photoshop" or "cut out object photoshop" - though the latter will probably be mostly people which is far more advanced than a cabinet.
You can try a quick method if your background is white enough: Open image. Go to Select > Color Range and use the dropper to select part of the background (somewhere next to the cabinet). Use the "fuzziness" slider to try to get it to select as much of the background without too much of your subject. Focus on selecting the area next to the cabinet, the other part is easy. Then go to Layer > Layer Mask > Hide Selection. You can then use the paint brush to hide more of the background by painting with black, and show any of the cabinet that got deleted by painting with white. Once done, put a white background beneath that layer. It sounds more complicated than it is, but if you've never used these functions it's really going to help to see someone do it.
Here's a better way to do it, but it's a bit more advanced, and more for touching up a mostly good background. The guy who does it, Aaron Nace from Phlearn, is fantastic. I recommend finding some of his vids on Youtube or Phlearn.com
How To Clean Up Your Photo Background: Photoshop CS6 - YouTube