I don't have a Multi/IR so am not in a position to offer specific advice, but I take issue with QNH 1013's suggestion that "if you make a mistake ... point it out to the examiner so he / she knows you realise ...".
Occasionally this might be good advice, but - depending upon the situation - one might often be better advised to keep silent and not draw attention to the problem. Examiners are only human and they can't catch all of your mistakes, so you might get away without penalty. That said, I certainly agree with the recommendation that you must fix the problem rather than just sitting there ... but be subtle!
MLS-12D
P.S. There is an 8-volume series of books called "The Instrument Pilot's Library" (published by Belvoir Publications) that you might want to take a look at. It is by the editors of "IFR" (
www.avweb.com/sponsors/belvoir/ifrmag/index.html) and "IFR Refresher" (
www.avweb.com/sponsors/belvoir/ifrref/index.html)
P.P.S. I don't know much about the cram courses that are available, but here's one person's experience:
www.avweb.com/articles/picdiary.html