Unless you have deep pockets and are collecting for the potential investment, I would suggest buying what you like and enjoy listening to. If you ever see any of your purchases increase in value, consider it an unexpected bonus.
If you are going to listen to your records (rather than just collect them) you should also invest in some record cleaning equipment. It will make a big difference in your listening enjoyment, especially if you buy used albums (which may have dirty grooves not immediately visible to the naked eye.)
If you buy used vinyl, record shows are a good place to buy for less than you would pay for a used record at a retail store. Always take the record out of the sleeve and look at it in good light to check for scratches/imperfections which will affect the value and listening enjoyment.
I generally find record shows to be about 30% to 60% cheaper than retail stores for used vinyl.
And sometimes you can find private sellers who just want to unload a collection for really cheap money. Usually because they are moving/tired of having it/it belonged to someone else who is no longer with them.
If you buy new vinyl, keep in mind that some newer releases are just digitized recordings copied to vinyl. I stay away from those and just stick with analog recordings.
After all, if I want a digital copy, I can just buy a CD or download the album.
Always try to buy the best quality you can afford to and don't worry about the possible resale value down the road. Some of your purchases may increase in value but most, probably, will not.
Here are 3 sites you may find of some interest...
The Record Collectors Guild :: A website for the Record Collector. (News)
Dust & Grooves ~ Vinyl. Music. Culture
Record & Stylus Cleaner