Arm chair fly an IR test as often as possible and the key to passing is to PREPARE. Have all the main possible airports and approaches mapped out in your head. Despite the stories you will hear the IR examiners are usually very fair and a mistake does not mean a fail, if you make a mistake during the test, correct it then forget about it and carry on flying the a/c.
Never try and bull !!!! the examiner if you dont know an answer say so, this stands in any sim checks you will have in your future career.
Good luck, you will remember your IR for the rest of your life! enjoy it!