Always lean - and always fly as high as possible.
Came as a big surprise when on a trip in France a couple of years back I got my Warrior down from 34 litres an hour to 26 (Cruising at FL75). That's a saving worth having.
Just wait until you move onto something like a Seneca. In that you have a fuel flow meter - almost straight after take-off you pull the fuel levers back to 15 gph in the climb - then back further to 10gph in the cruise. Really unsettling the first time you do it as it's totally against everything you were taught in a small single.