Hi Christina,
From looking at what you've shown and said, what comes to my mind is: First, take your time. Shadows and light are very important elements of your image. Getting a good skin and fabric texture are more important than the background. I would also suggest that unless you have lots of time to work on this picture, that If you add a mixture of colors or lights and darks you can achieve a pleasant, flattering background without laboring over details like furnishings or even the flag.
Simmie Knox has some beautiful examples of this technique on his website. Although, I have to say, hard as it would be to have to choose, my favorite painter of men in suits is also
Dean Paules.