A lot of the feeding depends on the snake. Here are my general guidelines for feeding:
I like to weigh the snake and weigh the rodent and feed up to but never over 10% of their body weight. If you offer too big of a rodent they will most likely ignore it and sometimes it will make them go off of feed for awhile. If you offer something too small, say a pinky mouse to any size ball python, they will ignore it as a food item. I'd say anything in the 5% range to 10% range is perfect.
For new snakes I go by the age and body weight. I got a free normal ball python that was a year old and probably not much bigger than yours. They were feeding her one fuzzy mouse per month! That basically starved her. When I got her she immediately ate three adult mice all in one sitting. I power fed my little girl and she grew like a rocket and made up for lost time, she is now over 1500 grams, she gained that much in about a year. Now she is off of food again LOL.
I like to feed my snakes a lot when they are eating, that way when they go off of food they have the body weight to sustain them and I don't have to worry about starving skinny snakes that won't eat.
I also like to go by the head size and body size. If the snake is looking fat I'll cut back on food, will even stop feeding for weeks at a time or even months to get them back down in weight, or just feed something small every few weeks. If they look skinny I'll really crank up the feeding to twice a week or more. I also go by the head size, a small snakes body can grow really fast but the head can stay small. In that case I'll cut back and let the head catch up LOL. It's usually from massive power feeding.
I also switch back and forth between mice and rats. I have one 'white wedding' spider pied female that has decided never to eat a rat, she will only take mice LOL. Not that it's a bad thing, I have tons of mice that I'm breeding. I usually give my mice to my King snakes and smaller ball pythons.
I also tend to feed my females more often, bigger size meals, and take more time and persistence in feeding. I really want them to gain as much as possible so I can maximize my egg production. Once my males get up to around 1000 grams I could really care less if they eat LOL. I still offer them food on a regular basis though.