As someone who has remodeled and sold houses for almost 43 years, our solution was simple, NO Curtains. We just put blinds in on every window. Plain white or cream colored.
 
They cost us between $4 to $6.00 a window depending on size.
 
There never was any window covering in the curtain department that made any buyer happy with them.
 
But no one ever complained about blinds.
 
So over 400 houses later... Blinds would be my suggestion.

Other tips and answers from Arlene:

 
You will only be considered a real estate professional if you are licensed.
 
You will be considered a real estate investor if you own any real property other than the home you live in.
 
I was both for almost 43 years.
 
Profit is profit regardless of what you are labeled. When you make a profit you must pay taxes on it. So make sure you keep a separate book keeping record for each property.
 
It is a good idea to keep everything separate for each property.
 
When you paint rooms... make sure you use antique white or off white.  Remember, just about everything you do might be changed by the new owner.
 
Go to seminars about real estate investing.
Jack Miller seminars are great!!!!
 
Buy books at half.com about real estate investing.
 
I have a book I sell for $29.95 Called Correll's Megapack Book (or the World according to Correll) and it is all about real estate investing.  The s&h is $4.75.
 
We no longer do re-habs, but up to about 5 years ago, we had done probably a couple of hundred of them over the years and probably 2 x's that in just buying and selling and probably in the 1000's from when I owned 5 Realty World Offices in N.Y.
 
When you cannot find blinds that fit in the window, buy the next size that go over the window.  It does not matter.
 
Keep you carpeting neutral.
 
Put a little landscaping around the front entrance.
 
Try to always include a refrig, stove and dishwasher even if they are used ones, because that is an added expense for the buyer.
 
Landlord sucks. I have been there a bit and quickly decided if they were going to be the tenants from hell, I was going to be the landlord from hell. I never took a sob story.
 
Buy and sell, buy and sell,
 
If you live in each one as you fix up, then it is not an investment property, but your own and you can carry the capital gains into the next one fairly easily.
 
We did that most of the time when necessary, but usually had about 5 to 20 others we were dealing with at the same time.
 
Hope this helps.