First, don't overspend for your neighborhood. If you're in a neighborhood of 50,000 dollar houses, sorry, you can't spend 40 grand on a kitchen. It won't return as much as it costs. Don't aim to be the most expensive house on the street.Second, the highest returns will be on fixing flaws. If the house is pretty nice except it still has granny's 1959 kitchen that's where you spend. If your neighborhood has high parking demand and you only have one space, look to double the driveway, add to the garage, or add a pull-off. If there is no dishwasher that's a flaw. No over the stove microwave, flaw. Window ac instead of central, flaw.Third, maybe the flaw isn't fixable, like being on a noisy road or next to a fast food joint. At least diminish it, like triple-pane windows on that side, a berm, a fence, and/or bushes. If you have a yard where grass doesn't grow, switch to a low water landscape plan that doesn't use grass. Diminished flaw.Fourth, first impressions count. The front entrance should be boldly colored, attracting the eye. It should be widely framed, well-lighted, and easy to approach. The front door lock should be smooth and easy to operate. Remember that the showing agent will be keying in through that door. The driveway and sidewalk should be powerwashed. Landscaping should make the yard look big, no clutterFifth, the thing that always adds way more value than cost is paint, inside and out. Make an empty canvas with your paint with very light shades and completely white ceilings. The art and furnishings are the color not the walls.Sixth, finished basements don't pay. They have low ceilings, inadequate windows, noisy mechanicals, and most people after spending money on finished basements discover they barely use them, too dark and too separate from the main quarters. The exceptions are if you are fixing the flaw of way too little square footage, have a walk-out basement with daylight windows, or can add a bath, kitchen, and outside entrance for a Mother-in-law type or even legal separate unit. Mostly I like a very light finish in basements. Just make the space bright, clean, and very sparsely furnished. A big empty space is appealing to buyers. They can imagine their own use. Don't clutter it with a pool or ping pong table. Maybe lay down a light colored rug but not wall to wall carpeting. If the house has the flaw of too few bedrooms then finishing half the basement might pay. You might need to dig out a window well to be an emergency egress, otherwise by building code it's not a bedroom. Besides then you have some natural light.Seventh, don't exceed conforming use. If most houses in the neighborhood are three bedroom then paying for a fourth bedroom adds less than its cost, and adding a fifth is so non-conforming it adds 1/10 the cost of building it. The exceptions are when you get it cheap. Say for example you are building a detached two car garage (in part because nearly all your neighbors have large garages and yours only has a small one car attached. That's a flaw. See number two above.). Turning the old garage into a bedroom cheaply could add more than it costs. If you are in a two bed house in a three bed neighborhood you are fixing a flaw, see number two above.If you are in an affluent area of 3000 sf homes and you have 1900 sf then an addition could pay, but you don’t have to go big. Get up to 2500. I’ve been in big houses with tons of wasted space, little hallways here, there, everywhere. It’s ok to trail the average a little. Be efficient.Eighth, a “light” remodel can do wonders. Maybe in a bathroom after painting I’ll replace a faucet, the curtain rod with one of those curved ones, and the light fixture with a multiple bulb LED. It’s not a gut-to-the-studs renovation, but it can freshen up the space considerably.Ninth, perception is value. For example I personally don't think radon is near as dangerous as most people do, but I know their perception affects value. So when buying a house I test for radon, get a clause in the contract, and do the mitigation. I know I'm going to sell some day. Those that perceive a problem will let it affect their desire to buy and willingness to pay more. I'd rather nip that in the bud so when they test for radon it comes in below the 3.9 pico-curie action level. Flaw fixed. For the same reason I remove lead pipes and buried oil tanks. When I go to fill out the seller's disclosure form when it comes to lead pipes and oil tanks I check the box no. Flaw fixed.Things that make it more saleable add value. If it’s appealing that’s value.Also if by clever decorating you can make a space "feel" bigger then that's perception. It works on real estate brokers and appraisers too. There's room for subjective shading adjusting values for the CMA.Tenth, value is determined by buyers not sellers. If you have a pencil to sell and ten possible buyers in front of you then the value is whichever buyer will pay the most. If you have one hundred buyers then whoever among them willing to pay the most determines the value. If your pencil is odd, like a strange color or only is comfortable for lefties, such that nine of ten buyers would reject it then you have a non-conforming property that will take longer to sell and get less money.There is no absolute value. If you spend 40 grand on a stupidly designed kitchen you can't hold a gun to the buyer's head and demand your money back. You have to be smart but humble, with understated style, conservative (but not cheap) in spending on improvements, and put yourself in the buyer's shoes.All the advice above is pretty standard stuff. Most good appraisers and brokers will agree, but I do want to add one little thing that's different. I like a little hook, something memorable. If a couple of transferrees are being squired around to ten houses on a Saturday by a rookie agent I want them to remember my house for something interesting or amusing, a theme perhaps, like dolphins, an interesting piece of art, a water effect in the yard, or just anything that'll make them say something like The House with all the Pumpkins instead of 123 South Maple Avenue. I want to stand out a little, be memorable.I hope this lengthy answer is helpful and concise. I also have written about priorities in building a house and how to stage a house for sale. I welcome feedback in the comments. I would love to learn something new and make a change to my advice.Daniel Sheehan's answer to What are the most important aspects to consider when making an affordable (200k) house feel spacious and luxurious?