First, understand the conversion thoroughly. Whatever metric figure you are given, multiply by 3, add 10% to that figure, and round up a little bit. Then you should read either Aerad or Jeppesen Route Guides to understand semi-circular altitudes in those areas. Then you should reread your Flying Manual sections about using QFE instead of QNH.
I found operations into Moscow and Leningrad difficult. You are flying to peculiar atitudes that don't mean a lot to you. When I had 'you are 500 metres left of track, 30 kms from landing descent to 2300 metres' sort of thing, I found it hard to work out high/low/where the hell I was. Take it slow and in good time.