The current walls are painted in a variety of colors, some dark, some more neutral.

This might be my favorite color scheme.

But, just to add some color.

Will put grey epoxy with "colored sprinkles" on the surface to help seal the concrete. 

Second, I think you are still looking at this experience through rose-colored glasses.

Be sure to use bright colors and strategic placement to your advantage to maximize exposure.Perhaps even more importantly, however, you’ll want to memorize the property’s details to answer any inquiries with an authoritative and confident voice.

I think whenever you are getting advice from someone it's important to always consider the source to identify the incentives that person has to give a certain answer and how it colors their thoughts.

First thing I would do is swap out the daylight color bulbs with a warmer tone.

I see lots of people with unrealistic rose colored proformas that I hope will be saved by an appreciating market. 

It’s not huge , it’s a single car garage if that helps  9' shuffleboard table would fit a single car garage nicely, but be sure to dress it up the rest of the garage as already mentioned.