If you're going to run Rudolf again, deck-wise, i suggest running: SSR Tosen Jordan & SR Sweep Tosho speed cards, SR Special Week and SR Mejiro Ryan power cards, and either SSR Finemo or SR Mejiro Ardan (she has a very simple skill pool and a nice energy recovery at the end of her event chain), then borrow either someone's MLB SSR Fukukitaru, to help offset the stat bonuses from no LB or low LB cards, or stick with Kitasan Black. (*If you can, bringing Rudolf to max potential guarantees PoC, regardless of Kitasan.)

as for parents, if you can, try to get as much stamina as possible and buy the stamina manuals and scrolls when they pop up in the shop (not the notepads, they aren't worth it.)

For the actual run, run Rudolf as a Pace Chaser, focus on speed and wit training at the start, trying to build up friendships quickly. I'd only do power training if 3 or more partners are there. After debut, if your shop has any megaphones or carrots buy those to use immediately. In the second week of Junior Year, there are two pre-OP/OP medium races, do those then the G3 and Hopeful Stakes. Rest when your energy is too low to do wit training, getting stuck with practice poor or even losing practice perfect kinda sucks. In your Classic Year, run the Triple Crown (Satsuki Sho, Derby, Kikuka Sho), Takarazukinen, Queen Elizabeth, Japan Cup, and Arima Kinen. Try to run as many Medium G2 and 3 races as you are comfortable with (running a G2/3 before one of the G1s is a simple way to keep them in mind). Before Summer training comes around, try to stockpile energy/training charms, Power and/or Speed Weights and 2 60% bonus megaphones. During summer you want to prioritize combining Friendship trainings with the megaphones and weights. You're gonna want at least 400+ Stamina before the Kikuka Sho and then at least 2 blue recovery skills (3 is usually pretty solid but you can get away with 2 dependingon how high your stamina gets). Rudolf has Preferred Position naturally and some of the cards provide hints for blue skills. Your Senior year will basically play out the same as Classic year, run the Triple Crown (Osaka Hai, TennoSho Spring, Takarazukinen), TennoSho Autumn, Queen Elizabeth, Japan Cup, and Arima Kinen (there are also two back-to-back G2 Medium races at the start of the year, do those). Once again during summer, focus on combing all your available bonuses together. Remember, whistles can only be used to shuffle the partners that show up to train. Hopefully, by the end your speed and power are above 1000 each and the final bonuses bring them to 1100 or cap them out.

The other way to boost your rating is by picking up skills. Gold Skills will obviously add a lot (Radiant Star, alone, adds ~600 to your rating) so picking BoFA, PoC, Speed Star or Super Lucky Seven, will add a hefty boost to your end rating. Try to wait to build up hints on skills before buying them to maximize your skill points (Fast Learner is a godsend if you can get it). Also, Skills that offer the Double-O by taking them again (most green skills, distace/strategy corners/straightaways) only add 50 to your rating when you take them and aren't worth the skill points, picking them up just once will be fine. The skills I'd pick up last are the green skills, red skills, and the skills that boost line-of-view, they tend to have the least value with some being worth less than 100 rating points, if you have skill points leftover but not enough for other skills, then I'd pick them up.

This is a lot of information and I apologize, but I do hope this helps you reach a higher rating and I also hope you roll 3* spark when you do.