For the IR make yourself very familiar with the approach plate layout so that you know exactly where to look for the information you want. I also strongly recommend that if you know most of the places you are likely to use for your training and test then learn these specific plates and profiles inside out so that by the time you come to actually fly them they will be second nature.
For the CPL make sure you are up to speed with your flight planning/performance but otherwise make sure your flying isn't rusty (a lot of people have just spent the last 6 months or more doing their groundschool) and go into it with the right attitude, which it sounds like you have.
For the multi revise the implications of asymmetric flight and also fuel systems, which can be a complicated beast in certain light twins and often neglected. Make sure that you fully understand these situations rather than just knowing what actions to take.
For all of the above, ask your training school to send you the checklists for the aircraft you will be using and learn them well, but particularly the numbers (power settings, speeds etc).
Hope this helps. Good luck,
NF