If I have used 4 toothbrushes per year as recommended by the American Dental Association than that means I've contributed 116 toothbrushes to the landfill or ocean (since I have no control over what happens to my garbage after it leaves my house). In case you can't tell I've been alive for (almost) 30 years. Considering you don't have teeth for half of your first year of life, I didn't count year one in my calculations. But that is still a high amount.
Remember that even if you aren't littering your waste could still end up in the waterways. It could have been shipped overseas and fallen off a barge. The garbage truck could have had an accident and your neatly wrapped bags could have flown out into a river. Lots of things can happen when that garbage leaves your house.
I believe taking responsibility for your waste starts with taking care of it (or at least your bin)
When I started working at Jimmy Johns while in my late teens, early twenties, part of my job was wiping out the garbage bin after every time the trash was taken out. The bin was to be wiped down inside and out with a bleach/water combo. This keeps the bin clean and prevents the buildup of sticky gunk. So I started this practice for my own bin in my house. I've continued it ever since. Sure some people think it's strange but I'm more cautious with what I throw away and how I do it as a result. I recently took this further and cleaned out the big bin with an old sponge and soap.
I'm sure my neighbors think I'm either crazy or at I've had some sort of really disgusting spill to brave that, but I don't think either are the case. I simply believe that you take better care when you are the one responsible for it. If I had to handle all my waste on my land then I would be super particular about what got thrown away. It's a very different thought process from most as the, out of sight out of mind, thing comes into play.
So here's a picture of my newly cleaned bin! You should take stock of your waste too and send us a pic of your clean bin!
It really helps your relationship to your waste. I know that sounds especially silly, but to begin having respect for your consumption and subsequent waste, I believe it's the first step. Start with your bin in the kitchen and bathroom if the big one is too intimidating. Work your way up from there!