For today's jobs I use one of those little paper pocket folders that your kids use to submit their reports for school that can't just be stapled in the upper corner. Huge investment of about 10 for $1 in the back to school sales.

The pocket on the right has at least one sheet for each job I'm doing that day with the address and a paperclip on it. The sheets are sequenced in the order in which I will do the shops. Notes on that sheet are the odd things I am most likely to forget so I can take a last minute look before going in. When I come out I will make some quick notes right there in the parking lot with my cell phone to my ear as if I was talking to somebody. I clip the receipt or business card to the sheet and move it over to the other side of the folio. Now I'm ready to move on to my next shop. I keep spare clips hooked onto the folio for the "just in case" scenario and the pockets are also great to capture brochures etc. I may be picking up.
Once the report is entered, all my paperwork staples together if I don't have to mail it in, and goes in the front of the month's file folder. That way it always stays in date order if I have to find anything.
When a folder is 6 months old it goes out of my little milk crate size bin of hanging files and into one of those plastic shipping bags that UPS and FedEx have as supplies in their curbside deposit boxes. I can get about 3 months shoved into a bag. The bags get labeled and when they are a year old, they get sealed and thrown in the box in the attic.
I am comfortable using Excel, so my shop sheet is a workbook of monthly pages and pages for other information that is live and active on the computer. Pages and totals link back to a recap sheet where I can see exactly where I am for the year. Expenses entered also feed back to the recap sheet by category. I have a page at the end of the workbook to copy and paste each month's jobs so I can keep track of the productivity with each MSP I have worked with and check when I last did a certain location to see if I meet the rotation requirements for the current job. Because rotation can be as much as a year and a half, I copy the full production for one year onto a sheet in the back of the next year's workbook. So when I open my shop sheet I have at my fingertips everything I need to know or keep track of.
My shopping clutter is 1 milk crate type hanging file folder bin, a pencil box with pens, card reader for the computer, paper clips and scotch tape. I then have a little tote bag that has batteries, DVR, microphone, cables for the DVR, a couple of back up jump drives, my camera, my spare SD cards for the camera and my stapler. In the bottom of the tote is a zippered shaving kit that has a spare power cord for my laptop, the voltage converter for when I get sent abroad, the power converter to use my laptop in the car and spare cords to recharge my cell phone. All cables are labelled and are stored, coiled in ziplock baggies except my spare power cord for the laptop. Batteries and my microphone for the DVR are also stored in ziplocks. Now if I could only remember to take the empty soda cans out of the car at the end of a route of shops I would be in great shape