I worked for a government shop in Montana for about five years. They had absolutely no process. So, the longer I was there, the more responsibility I gradually took on. Eventually, I was working on 5 or more projects a day. On top of that I was also doing quite a bit of user support, project management and Q/A. A man of a million hats.
Originally, I tried to track my completion using the 80% rule. It seemed I was always 80% done with everything. Usually was done with coding but I still needed to deploy my code and get through some initial user feedback. Time spent on deployment doesn't seem as "productive" as writing more code, so it never seemed to happen.
Eventually I developed a more meaningful way of tracking work and I use it to this day. I started making a cue card for every task that I needed to do in order for a project to be finished. I could break a cue card up into as many child cue cards as I wanted, whenever I wanted. I put the cue cards somewhere that my managers could see. I used the side of my cubicle but just putting them in a stack on your desk works, too.
Whenever I started working on a card, I put it on the In-Progress stack. When I finished, I moved it into the Complete stack. I even had a stack for interrupted tasks (for when your boss comes over with a great idea or a user's machine set on fire).
I received a lot of positive feedback for this approach. I got various pizza parties for doing exactly the same amount of work. The idea is that this approach helps management realize just how much work is actually being accomplished.
I'd recommend writing up as many cards at a time as you can. It can take a little time and experience to come up with a stack of cards. Just remember you can break cards up later if, while developing, you realize there is more than one thing involved. The bigger the stack, the more it looks like you're getting done. It also helps you come back after a break and pick up where you left off.
I've found just having a card say "do x" helps me stay on task. Without cards I tended to spend too much time switching because I had to "decide" what I wanted to do next. Just from personal experience, I've notice a massive increase in productivity and a major decrease in stress - that feeling like your lost in a sea of work.
It turns out there are a lot of awesome tools for creating "cards" electronically. I've only worked with a few tools that simulate the "card" well. I still prefer to see a pile of cards on my desk. The whole Kanban workflow involves similar cards and involves a pull-based system for limiting the amount of concurrent work. I guess a lot of people have stumbled upon the same thing that I did