As a certified Bad Player (with rating to support my assertion) I have
ditched almost all of my opening books. I don't have a lot of spare
time to study, and something like 95% of that time is spent on the
Chess Tactics Server or with the CT-ART tactics training program.
This does me far more good than any other study plan I can think of.

The other 5% of my time? Chernev's "Logical Chess Move by Move" is
probably 3% of my total time, and opening study is maybe 2%. I just
want to have a few ideas and know a couple of short and simple
sequences. At my level that is more than enough.

Against 1. e4 I play 1. ... d5 and please don't tell me about it being
inferior in theory. It gets into a wide-open game that is sound
enough.

Against 1. d4 I go for the Tarrasch and take my chances. I know it
to a depth of maybe 4 moves; that's enough for now.

Against other stuff I try to transpose, for instance 1. c4 e6 as often
as not will get me back to the Tarrasch, and if not, I just play the
best I can.

With White, 1. e4 and again I know maybe 3 moves in each sequence;
play for an open game (French and Caro-Kann exchange, for instance).

I do try to be consistent so that position patterns often repeat.

One exception to all of this: if I feel I do really poorly in some
opening variant in a particular game, I'll likely look it up
afterwards to try to see where it went wrong.

But again, when I have time, it almost always goes into tactical
practice, because I have no illusions about my losses --- they are due
most of the time to the type of mistake which tactical practice can
help eliminate. And my wins, such as they are, are due to taking
advantage of the opponent's similar mistakes.