"Accordingly I’d like to say a few words about how one should select a good coach for the sake of both the genuinely good coaches and those who wish to master our noble game. First off the guy should be able to walk the walk and not just talk the talk, so you should look for decent PLAYING STRENGTH from someone who has ACTIVELY PARTICIPATED in tournaments. Ideally they should still do so; when players stop playing they get all sorts of unrealistic notions.

Also note that anyone who claims that mastery of chess or any other art form can be achieved via some quick fix is a charlatan. Watch out for too much sales patter, manufactured qualifications (for example attempts to show linkage with well known PLAYERS), use of puppies to show how nice they are or a focus on players who will improve just by virtue of getting older (the young!). Also watch out for the teaching of opening tricks starting with Scholar’s Mate (for the under 8s) and progressing on the Fried Liver Attack. This stuff may achieve short term results but at the cost of a player’s long term development." ~ Nigel Davies Blog

Bravo, Nigel! This is precisely the sort of thing I've been preaching on this blog for the past two years!