Hi @Marian Smith. It's all local and it's all based on comparable sale prices. I wouldn't think Zillow or anyone else has put together anything of much use on a small, local scale. Your best bet is to comb through "closed" sales. Using comparable square footage, compare the ones with redone kitchens and baths to ones in the same neighborhood with old kitchens and baths. Three bedrooms to four bedrooms. You get the idea. In my area, I know appraisers add $15,000 for a pool, $2500 for a built-in spa, $10,000 for another garage space. They observe the materials used in the home and make calculated adjustments. They adjust for views, landscaping, and other amenities according to their judgement. As far as a community pool or other community amenities like gates or guards, everyone in the community has them and the appraiser will probably only use comparable from the same community, so it's a moot point.
If you have a burning question, don't be afraid to call a local Realtor and just ask. You might even find one here on the site that you can PM.
Another tip, pay attention to homes that have been "flipped". Be on the lookout for homes that have sold less than a year before and pay attention to the work that's been done and what the price difference is.