Some Helpful Guidelines:
Best to use houses that have closed in the last 3 months or less, only go out further if you can't find anything but only up to 6 months but I generally limit to 5 months.
Only go 250 square feet less or more than the subject property
if the subject has a pool try and find homes with pools and if it doesn't have a pool try and find homes without
Whatever the property is in general you need them the same, then can have 1 or 2 better (meaning pool v no pool) and then 1 or 2 without pool so if it has a pool you can't have 3 without pools and vice versa
Compare block house to block houses and frame to frame but use the same rule of thumb as the pool explanation above
use similar years so if it is like a 1990 house I will search 1980- 2000 and expand only if I need to
Always start with the neighborhood the property is in and then go out from there
I always ask the seller what they think the house is worth so I can use that as a guide to see if I can hit their number when pulling comps. If I can, great, if I can't then it is what it is.