For me, I use my iPhone's camera and rely heavily on pictures to keep myself on-track.
Ex. I type my notes on the "notes" app on my phone, then screenshot it. I Geoverify my location, then screenshot it. I take a picture of my 'start' mileage and my 'end' mileage. I screenshot my clock for 'start' times and 'end' times for each shop. I take pictures of my receipts, documents, etc. Then when I'm finally on my laptop, I plug my phone in via USB, then drag and drop the pictures to their respective folders.
For long routes (basically anything with 5+ for me), I "assign" simple shop ID's for each assignment; this becomes useful, especially when I'm shopping different locations of the same client. Typically, I just name it whatever matches up with my route map (I usually use Mapquest for this), and name it that way (Location B, C, D, etc.). I find it easier to remember Location A and B, instead of street names.
Of course, what may work for me, may not work for you.
Shopping the Greater Denver Area, Colorado Springs and in-between in Colorado. 33 year old male and willing to travel!