MTs are the sparks you get while drifting. As for practicing drifting... Here are the courses I recommend practicing drifting on:
-Airship Fortress - in that U-turn at the beginning, practice until you can consistently go between the moles and the wall. It helps a lot with your precision.
-Bowser's Castle
-Neo Bowser City for obvious reasons
-Cheep Cheep Lagoon - you need to learn how to drift between the clamshells and the wall if you don't want that course to turn into an automatic not-good-placing
-Waluigi's Pinball, because it has very tight turns that are great for this.
Anyways, once you get decent lines and get a good kart combo together, the most important thing to learn is good item management. Mainly, the following points:
-Get into the habit of looking at the bottom screen regularly. This takes some practice; I recommend starting out by learning to do it on the straightaways. Once you get that down you can do cool things like:
-If someone has a red shell and you have nothing to defend with, stay behind them until it's safe. Else they'll just nail you.
-If you're close behind 1st and see a blue shell pop up, be prepared to brake in case they try to brake to nail you with a Blue Shell.
-Some people in 1st brake regularly. Then 2nd brakes. Then 3rd brakes. Then 4th brakes. Then 5th brakes. Then the person in 6th suddenly becomes 1st with a Blue Shell and you're all screwed. This is why you should only brake in 1st if the person in 2nd is literally right behind you; at high level play, if they have enough time to react they *will* brake, and said scenario will occur.
-If you have a red shell and the person ahead of you has a Tanooki Tail, wait for them to lose their tail before firing your red shell. They'll be an open target the moment they lose that tail.
-If you get a Lightning and the course has a huge gliding section, save the Lightning for that gliding section. It'll be worth it.
-If you get a Blue Shell, always wait a few seconds to see if the braking scenario I mentioned earlier occurs. It doesn't happen much in our rooms, but in like 40k VR rooms it happens all the damn time.
-It's usually better to leave bob-ombs behind you than to try to snipe somebody with them. It's 100x easier to get someone with a dropped bob-omb than a snipe.
-When possible, save your bananas for blind spots. Don't be that person that always winds up using their bananas right before an item box because they weren't paying attention.
Then there's some fancier stuff you can do, but a lot of that involves figuring out who has red shells and what's safe and blahblahblah. Also, I think that's enough for you to practice for now, anyways. ;P