Slick graphics are a surefire way to have a game that looks polished. But for the art-challenged developers out there like myself, what are the options?

Shameless plug: please rate my game :-) https://ldjam.com/events/ludum-dare/40/a-stack-of-gifts

I've found there's another level to "polishing" and some easy things (which admittedly I skipped out on a few myself this time) one can do. Here's my top 5:

1. A small animation left or right is subtle yet unconsciously adds to polish. In my Stack of Gifts game this LD, I have animated the text announcements when you get a powerup or get extra points for a trick. The animation system in Unity provides an easy, visual way to set where and how the text moves, and it's time-based. I tweaked how long the text was visible as I playtested. Simple. And, about an hour before submission I noticed the powerup wasn't clearly a powerup. It looked like a gift and too much like a UI icon or something. So I made it slowly move in a circle and low and behold it totally looks like a powerup! Half hour before submissions I swapped my stupid static background of paint-like Christmas trees for Blender-made low poly cones looking like Christmas trees, and gave them a random-colored light turning on and off. Again, easy work but adds some subtle polish.
2. Text. I totally skimped on this (except for the title screen) but: change the default fonts to something fun! For static text in UI etc - just use a cool font in your favorite image editor and add it as a UI image instead of using the text features of your game engine. If you have time left at the end, color them in or texture them or something. Yeah, I missed this one.
3. 3D shapes. With Unity it's easy to add a block or sphere or whatever and make some 3D structure resemble something. But honestly it doesn't take a lot of effort to learn to do those basics in Blender too. Once you're there you can add a few more touches to make it less "standard shape" looking. Or split up the shape in multiple shapes allowing for easy coloring of different parts without texturing (see the santa in my game). And, if time permits in the end, UV unwrap and actually add a texture. My game is actually 3D and I had more plans: the sleighs at the top are actually 3D objects, not an image. But it didn't look cool enough and ran outta time. But I did put a texture on it (again, it's not a UI image :-)
4. No time for music this time, too bad because your mood score will go WAY up immediately. You can find free publicly availablee stuff you can use if you're not musically inclined. But sfxr or bfxr are SUPER easy ways to add small sound effects to your game. Little effort but decent returns.
5. Again one I violated but - in Unity find a nice texture or something instead of the standard "panel" UI backgrounds. It looks too "default". Make a nice border you can use or something. Again small effort but it all adds up.

Hope you enjoyed my top 5 cheap polish tips. Now go rate some games, including mine here: https://ldjam.com/events/ludum-dare/40/a-stack-of-gifts