If your thinking of adding rooms or major improvement, dollar for dollar you won't get a return. The cheapest and most valuable items that can be done are simpler than may be realized. By just cleaning, painting and maybe new carpet the value of a home can go up drastically. You must put yourself in the shoes of a potential buyer to understand. Yes major items are important, but that which is seen is important to perception.
Many sellers have a sound property, but are lacking on the surface.
In a ruling by the IRS, even points paid by the seller are deductible. An amended tax return must be filed to take advantage of this benefit. Contact a tax professional for changes in the law. If the agent has done what they promised when the listed such as exposure in the multiple listing service, ads in local publications and open houses, the burden is upon you and it's probably the price. If you've had several lookers and received offers and just haven't come to terms, it's priced right.