Look at the gauge, then figure out how many inches the sizing works out to. It may be loose or close fitting, so for example the size 36 may work out to 34", 36" or 40". That tells you the amount of `ease' it has. Measure some sweaters you like the fit of and figure if they're your exact size or looser or tighter. That should help decide how the sweater you like will fit you, and you may want to make a size smaller or larger to fit the measurement you like.
sue- knitting heretic