First of all, you need to make your kitchen neat and clean. Your goal should be to make the cooking area very clean. Each and every surface and shelf should be shining. If you cannot do this job on your own, hire help.
Give special emphasis to the cleanliness of the stove.
After cleaning the surfaces, it is the time to work on the walls. Make sure that the walls are freshly painted, and have a warm, neutral colour. Even if the paint is not fresh, and you can't afford to get it repainted, use of wall pictures is a good and effective option.
Improve the light in the kitchen. There are many features within a kitchen that are often ignored because of improper lighting arrangement. While it is not advisable to illuminate the whole kitchen, and waste electricity, using small lights to enhance the major feature of the kitchen is a good way to add value.
Also make sure the flooring is in good condition. If there are any cracks, scratches or indentations, you should repair them. It is not a good area to hide the cracked patches with floor mats.
If there are any unnecessary appliances in the kitchen, remove them. There should be only a few items on display. A hanging pot rack would not give out a nice impression. Similarly, get rid of the stickers and other items stuck on your refrigerator. The entire kitchen including refrigerator should be clutter free.
In order to show off good storage capacity, keep only a few items in the drawers and kitchen cabins.
Also make sure the sink hardware is in decent condition. If the faucets and spray nozzles are damaged, replace them with new ones.
Place new, neat and bright dishes on the counter. A bucket of fresh vegetables and fruits will give a great impression. Also ensure that the door lock is in working condition.