How to keep my boots looking at least OK?

I know exactly what you mean. My boots get VERY dirty, especially in the winter. What I would recommend getting a bucket with water, rags, a toothbrush, cleaner, and conditioner. Wipe off any dirt you can with a damp rag. Then, use the rag or toothbrush (depending on how ground-in the dirt is) with leather cleaner, and clean off the rest of the dirt. Lastly, use a rag to put on leather conditioner (I use Neatsfoot Oil, but they do pretty much the same thing). Every once in a while, bring them into a cobbler and ask them to clean and waterproof your boots. It won't actually waterproof them, but it makes them more durable (and SHINY!) Hope this helps :)