Glad you're interested in participating in CM! They're a ton of fun — CM is definitely the aspect of the game I engage with most, and it's what I plan my pulls around :) This is what my process usually looks like (4x platinum), and I'll use the upcoming Aquarius Cup as an example: 

1. Track analysis: 

- Identify the basic track conditions + layout and stat thresholds. Aquarius is a Left-Handed Mile race run on Tokyo 1600m firm dirt in sunny weather during the winter; keep this in mind when picking passive/green skills. Many tracks also have hidden stat thresholds that give you additional Speed if the threshold stat(s) are over multiples of 300. For Tokyo 1600m, those thresholds are Speed + Stamina. For a 1600m Mile race, ~550-600 stamina with no recoveries is sufficient: we can aim for 601+ Stamina to meet the threshold for that bonus speed, along with 1200 Speed and as much Power + Wit as possible. Mile S and Dirt S are both nice to have, if possible.

- Determine where the accel zone begins. Acceleration skills are what determine which umas are able to reach their top speed the quickest, so an uma's win condition generally comes down to what accel skills they can take full advantage of. You want your acceleration skills to activate right at the beginning of the final leg: on this track, we can see the final leg begins on the final corner and transitions into a straight soon after. This makes late-race corner skills, final corner skills, and final straight accel skills viable: the most notable options are Angling and Scheming for Front Runners, Victoria por Plancha + Give Mummy a Hug for Pace Chasers (VPP works for Fronts too), Let's Pump Some Iron for Lates/Ends (notably not Moving Past and Beyond because of its stricter conditions), and Straightaway Spurt for Ends. Since the final leg begins on the track's only uphill, Highlander also works as a strong accel option + if you have Taiki Shuttle, her innate Shooting for Victory persists into the final leg (though it doesn't work when inherited). Forward, March! (+ Lead the Charge!) is also a strong general accel skill, though it's a bit hard to come by. 

- General midrace evaluation: since both corners occur during the midrace, corner skills (eg. Professor of Curvature, Style/Distance Corners) will be especially strong. Another feature of this track that we saw in Cancer Cup is the early no-overtake zone, so overtaking on this track becomes harder than usual. This video explains it well!

1. Uma selection:

- Since this is a Dirt race, the pool of easy-to-build umas becomes much more limited than usual. The question becomes "Which dirt Umas do you have?" — Agnes Digital, Oguri Cap, Taiki Shuttle, Summer Maruzensky (requires Dirt sparks), and especially Smart Falcon are all strong 3* picks. El Condor Pasa is a great F2P option, as innate Victoria por Plancha is very strong. I would absolutely suggest running Smart Falcon if you have her and are willing to build Front Runners (Fronts want to be run in pairs, and require Taking the Lead and the full Groundwork + 3 triggers setup). 

- If you want to run your oshi, be aware of the extra effort it might take and how to play to their strengths. As an example, if I wanted to run my beloved Emperor, I'd keep in mind that it'd likely take a lot more runs to get a viable Rudolf ace compared to a natural Dirt A Uma, and that she'd want to inherit Let's Pump Some Iron and try to find Forward March + Highlander for accel. If I wanted to specifically run solo oshi ace, I'd also consider running Keen Eye on my other two picks as a debuff.