Good for you in taking this step! Empowering isn't it?
Having recently gone through this, I will share my observations. What I did was simply take a bullet point list of my needs with a few assumptions. The list included the amount I was looking to finance, my assumed credit score, (which I already knew) the term of the loan, copies of my employement records (check stubs), W2's and tax statements. I then asked for each mortage company to provide me a itemized list of closing cost, title fees, intrest rate and monthly payment with escrow.
What I found was suprising. I went to 4 lenders. 1 was a bank, 1 was a credit union and 2 were mortage lenders. The credit union only called me with the info. ( I had supplied fax numbers, addressed and offered to come back and discuss) 1 of the mortage lenders wrote their proposal on the back of the envelope I brought my stuff in and the other two actually gave me what I asked for. Needless to say, I didn't go with the 2 who didn't provide me the simple service I asked for. In reality all of the quotes I received were very close in cost. In comparing apples to apples from my list, it made things easy to see.
Prepare your "list" of needs to insure you are doing the apples to apples comparison. AS with everything, be careful of the good deal. Typically, it is good for someone other than the customer. No need to rush into anything. Stay away from the variable rate and intrest only mortgage and lock in a rate at the shortest term you can afford. I"m sure you've heard of the mortgagae issues going on in the US. The reason is the marketing of the "good deal".