The bots in our games walk at a preset speed, as is how long they sit at the tables and 'eat' the food. Other than what recipes we serve, the only factors we, as players, can change or alter in making coins is how far the bots have to walk from door, to register, to table and back out again.
If you have your tables or register very far away from the door or have a lot of obstacles in the way, it will take your customers that much longer to come and go which slows down your earnings significantly. If you want to make as much money as fast as possible, you'll want to have your tables placed in a way so that the bots are in and out as quick as possible.
A few years back (I think it was 2017 or so) I changed my layout according the info I found in the forums on the subject and I've never had to wait more than a few days to sell out all of my food when I want to redecorate. If/when I think I'm spending too much and need to make a bit more coin, I make sure to set at least four ovens and four drink mixers serving the older recipes that give either 8 or 10 coins per serving rather than only using the new recipes which give 4 per serving. Between those two things, my bank is safe and doesn't dip down below where I want it.
Below is a list of a few of the links I can recall using and as I said, they are very old but still accurate and some of them are from RS but, again, we players in BS have found the info in them just as useful to this day.
- Client Calculator thread
here
- Most efficient layout
here
- Adjusting food consumption speed
here
- Fecs layout vs GroovyRuss
here
- Optimal door and register numbers
here