Any advice on buying quality vinyl

I think it is impossible to generalize. The attraction of the better audiophile reissue labels is new, usually clean playing LPs that may or may not sound better than an earlier pressing. It depends on the particular record, which usually means you have to dig down and learn about different pressings, compare them or rely on anecdotal comments from other people who have made such comparisons. I don't think there is one easy path.
The biggest limitation can often be the selection of material offered by the audiophile approved labels- in many instances it is the same stuff, reissued repeatedly, because there is an established market for known "best sellers." That said, if you need to fill out your collection of certain rock, jazz, etc. they are worth considering. 
But, if you want to push the envelope and look for less well known records, or are seeking out some records that have never really been bettered by modern masterings, you are in the world of older pressings. It is, for me, a continuing education, not just of the minutiae of pressing details (and how that correlates with sonics), but an ongoing exploration of different music that I wasn't familiar with, or simply ignored. This journey has led me to a lot of music I was unfamiliar with. 
For example, I had lost interest in straight ahead jazz. I had many of the warhorses- great records, to be sure, but I seldom listened to them. A friend turned me on to "spiritual jazz," a movement that took place in the early '70s after mainstream jazz became a dead letter commercially. I started to tap that vein- records from small labels like Strata East, Nimbus West and even smaller, private labels. Some have been reissued (Pure Pleasure has done a number of them, and despite their opaqueness about source material, the ones I've bought sound quite good and are far cheaper than the original pressings, condition is less of an issue, etc.). Speakers Corner did a remaster of Herbie Hancock's Crossings, another eclectic spiritual jazz record that is cheaper and in my comparison, sounds better than a time capsule original US pressing.
I think you have to figure out an entry point. Are there particular records you are seeking? You can research anecdotal comments on "best" pressings. Are you looking for new to you music? Lot's of things to read, and sample. There are any number of lists, including comments here and on other fora, about what people like.
This sounds like work, but it is fun work, and you learn quite a bit along the way about music history, pressings and your taste. I am also listening to a lot more different music than I did 20 or 30 years ago and really enjoy finding things that are a little off the mainstream path. Treat it as an adventure and you will be rewarded accordingly.

I wouldn’t assume that the ’original pressing’ is necessarily the best sounding copy either. On the early Elton John records, I found that the early DJMs from the UK sounded better than the US pressings from the same period. But among those, there are differences in sound, e.g. Tumbleweed has several iterations, with different stamper numbers and each sounds different, and that’s just among the UK pressings from a limited period of time.
@inna-- it’s more time than money in some cases-- but yes, even buying half a dozen different copies of a common record could add up. I’ve sort of backed into it many times, where I had some vaunted audiophile copy and compared it to a more common old record and preferred the latter. Not always though. As to anybody better than Miles or McLaughlin? I’m not sure that’s the point for me. I listen to a lot of different stuff.
The fun to me is finding records that are sleepers, musically and sonically, where you don’t have to pay a king’s ransom for something you enjoy. On the other hand, I have spent money on certain records, a subject we discussed at some point here, I think.
What’s also interesting to me is that a lot of the lore about different pressings really came after the fact, from collectors and bin divers and sound hounds. Many of the record companies back in the day just had ’em made and done- it was a commodity. Nobody was sitting there at the time saying "man, I really think the last pressing run we did was a killer."
I think there are deep narrow pockets of knowledge across the spectrum- some folks know Deccas, or EMIs from the period in classical, or Blue Notes in jazz. Me, I’m a dilettante -- I’ll find something interesting, do some research, buy some copies and see what I think. I also listen to a lot of early hard rock, folk, some prog, and each of those has its own following and knowledge base.
If I were just starting out, I’d probably look for Warner US pressings, typically the earlier the better, from the green label onward; UK Islands- , pink label, onwards; not that I shop by label, but both had good catalogs and pretty good sound. Plus, there’s a fair amount of anecdotal information on pressing variations on the web that is fairly easy to extract.
It’s a subject that is a full time job for collectors- but the collector thing is different than seeking out the best sounding pressing. You bang against collectors sometimes though, because the better sounding copy may also be rare or desirable. The cost of some of these can get nuts (and condition is always an issue, something I’m not sure the collector market is quite as focused on-- visuals and completeness are important, but noise free grooves? Good luck). That’s where the reissues can be a good alternative.

Wasn’t it "Dynagroove"- Dynaflex was just thinner, right? Hans Fantel was famously touting Dynagroove back in the day.
I don’t mind thinner records.
A copy of this came in yesterday, on this thinnest vinyl I think I’ve ever encountered. Staggering, sonically and sublime musically. Not easy to find. 
https://flic.kr/p/23WrviD