My car has its MOT test coming up in a month, what can I do at home to help it pass through and make it ready/easier for the mechanics.
I'll second Rory's points. I'd also suggest giving it a quick clean (especially underneath), so they don't have mud getting in the way when they try and check it.
You should already be checking your lights, tyres, fluids etc on a regular basis. If it is more than a few years old it is worth giving the seatbelts a visual check. Make sure there are no scratches or cracks in the windscreen. Make sure the washer fluid is full - A silly little thing, but it will fail if it is empty! If any of your doors are stiff, oil them so that they open, close and latch properly.
You hopefully won't have anything hanging from your rear view mirror, but if you have, remove it - it will fail for obstructing your vision.
It is all common sense really, if you've been maintaining your car properly you shouldn't have any major problems. Saying that, I've had bulbs fail on the way from home to the MOT garage!
A quick assessment of your normal consumables is worthwhile - do any bulbs need replacing, check your wiper blades, are there any visible leaks?
Check your oil, depending on your relationship with your MOT garage, is it worth replacing your oil yourself, or can they do it cheaply if necessary?
The only other thing I would do to make life easy for the garage is to clean out the boot so they can get at the spare wheel etc.
Generally, aside from wiper blades and bulbs, I would let my garage do everything - it is my cheapest, quickest option.
Most of the activities you should do to help your car pass an MOT are continuous throughout the year in terms of good maintenance and service practices so you can't really do much at this late stage to make a difference.