Here are some thoughts about what you mentioned:

There’s no need to buy anything for your compost, like potting soil. If you want to add dirt, just dig up some from your yard. The bugs in the dirt will help out your compost. If you drill holes in the bottom of your can, the bugs will find their way in there on their own, though.

Yes, oily stuff should stay out. Also meat, cheese, and bread/grain.

If your compost is soggy, it needs more dried leaves, straw or something like that. If it’s dry like straw, it needs more water or fruit/veggie matter.

I found the composting process pretty slow in the trash cans. The more often you can turn it, the better off you’ll be (every day if you can).

Congratulations on getting started! I find composting a lot of fun. I hope you enjoy it, too!

I’m sure Issa will have lots to say, but here are my two cents.

Whatever you do, don’t bother adding potting soil to your compost. Compost does not require expensive additions like that. It might be helpful to add some dirt to your compost if the moisture balance is not right, and to add some bugs, worms, etc… but mostly, just let it do its thing, turn it regularly to speed up the process, and try to keep your carbon-to-nitrogen ratio about right.

We found that our results were much better with larger piles. A 55-gallon trash can seems like it’d be a lot, and it feels like a lot when you have to roll it around the yard, but compared to our current piles (approx. 4x4x4 bins made from pallets), it’s a drop in the bucket. That being said, I know people who use small, approx. 25-gallon turning drums, and they have good compost, so size isn’t everything, but it’s something. Maybe they put a lot more attention into their compost than we do.

Currently, I think the biggest challenge with our compost is getting enough nitrogen. We use straw as animal bedding and after it gets all full of manure, it goes into the compost. There usually ends up being more straw than manure, and we just don’t make enough kitchen scraps to make up the difference. This means that it composts slower than it otherwise would, and at a lower temperature, but time is one thing we’ve got plenty of.

Best of luck, and don’t get discouraged if you end up with too wet, too dry, too much brown, too much green. Compost is very resilient, and you can probably sort things out and move on.