I agree with Ambar, but I would add that you need to find a place to store the things you aren't going to work on right away. If you don't have a place in your home where you can store these "projects" then you have to arrange such a place before you can start to clean off your workbench. Obviously this is easier said than done, but it is a problem you have to solve first. In order to store my quilt projects, I have a four-drawer bureau and two sets of shelves in the work area, and some other storage areas besides. If I didn't have this storage space I wouldn't be able to work on anything because my unfinished projects would be covering my cutting table and the floor around it and the ironing board as well. It doesn't sound too different from what you have. I have mending and broken things to fix too, and they are put away waiting for me to get to them in due time. I have a few things sitting out but now I choose the ones I want to look at, things that are attractive even in their unfinished state.
I have some bulky things that are on my project list that I have in a corner of my kitchen. I have to take a clock to the store to figure out how to make it work, and it's on the floor next to my filing cabinet. I have some books to send to people and they are in a pile in the kitchen near my project files. But they aren't in my inbox or mixed up with my reading material, they're just in a spot where they can sit for a while. If they were sitting in my inbox or with the books I want to read, they'd interfere with getting other things done. I think you need to at least pile your things somewhere besides the workbench, maybe by category (to return, to fix, etc.) and have these places ready before you start processing this "stuff."
To give another example, I have a dish I have to return to somebody. I just stuck it away with my own serving dishes. I won't forget about it because it's on my errands list. I had a doily I'd been meaning to give to my brother-in-laws wife. I had on my list to give it to her. When she showed up I went and dragged it out of where it was put away with other like objects. I didn't have to keep it in plain view to remember to give it to her.
I'm not saying you can do something exactly like these examples, but what you end up doing should probably look like them in principle. I do have to say it took me about six months so far to get things organized properly at home (at work it took half a day), and I still have some room for improvement.