Go in armed. Above all, know how much you can afford to spend and stick to that. If interest rates change in the mean time, adjust your affordability metric accordingly. But don't just go buy the house in an emotional way.
There is ALWAYS another house, another car, another bike, wife, husband, boat, pistol, etc. that you can buy later if this one doesn't pan out. Believe me on this one. If you're a buyer, keep the emotion out of it, be patient and let things roll along. You'll have several professionals involved in your transaction before it's all over and they all know what they are doing BUT ask every question you can think of and make them all earn their pay! They work for you so ask questions and give directions to them as needed. You may not have to give them much direction but ask them all the questions you can in order to drive them crazy!
When you get that pre-closing estimated statement of costs or fees (I don't recall what it's actually called) from the lender or broker, question all of the fees there as well. If you think something is a bit too high, take it to a competitor and see if they can beat it but be careful they don't take something away on one line and add it to something else. Keep a laser focus on the interest rate, of course, but also on the points and other fees.
Remember, if you buy a smaller house, you may be able to remodel it to suit your needs, ergo, big garage!
The financing of such a project, though, may be more costly if you don't buy the right house to begin with so I understand the emotional need to get it right the first time and avoid the hassle further down the road.
Look at this as a learning opportunity and learn to say, "Cool!" whenever you learn something you didn't know. The fears and stresses of it are all based on the unknowns so the more you learn, the less stress you'll have.
Have fun!
--Wag--
it huge with a work bench and if we got it all mine 
. 
then we went back and bought the 1st one we had looked at. 
