I'm no expert on the matter, just generally what I've observed over the years with a few moves:
Getting a good one really is research, research, research - surveys to find out things like flooding potential, common issues with houses/designs of that build era (often you can get a good idea from looking at similar houses in the area which have sold previously and comparing where it is possible to see it the work which has been done) and even looking at Google street view if there is coverage over a longer time period i.e. my brother in law's old house and the similar build ones around it you can see the fascia rots out and needs replacing over the period from 2008 to 2018. Getting an idea of any longer term developments in the area that might be disruptive like new housing estates, new roads, etc. (you can also use this to your advantage if it is something which doesn't bother you but might compel some people to move out because it bothers them i.e. new estate build near houses which were previously in a quiet area).
Negotiating a good price is more difficult - unless the house has been on the market for awhile, or they are desperate to move, most people won't want to go below asking price - being in a position to offer a minimal chain and/or having the money ready to go can make a difference there as some people will value the convenience factor over getting the best possible price for themselves - keep an eye on stuff which has previously been up for sale very recently and/or STC and pops up again as likely the buyer has pulled out leaving people hanging and more likely to accept a keen offer.