Your question is vague; it makes me ask why you're asking:
If the house is in bad shape, doing basic things like clean-up, painting, broken windows, etc will not only yield more than your investment, they make the sale possible.
Above and beyond that, Up-dating a Kitchen will get you 80% to 120% of your investment, with bathrooms right behind.
Be careful spending too much; beyond what the Comps or the neighborhood norm is; it not only will not help, it could hurt if the house is over-improved.
Good luck and may God bless