Practice in single-player
Although Super Mega Mini Party is a multiplayer-centric game, it does have a single-player mode that really comes in handy when you want to practice. There's no story or anything, it's just straight to the point, pick your game and play.
It may be wise to get as familiar as possible with each game. No need to play each game repeatedly or anything like that. Just try to get in a game or two. Sometimes, all you need to do is know the rules once and you'll be set and ready to go.
But, it's good to get used to the games before heading into multiplayer battles. But, if you feel like the best practice is to get into the real action, then by all means, head into the open world and get into some games. But, if you find yourself struggling, then you can hit the single-player games at any time.
Start with one on one matches
If you feel like you aren't exactly ready for a full party, then start with some one-on-one games (1vs1). You won't need to worry about the pressure of dealing with more players who are more experienced. Instead, a one on one can help you gain some experience playing against real players.
You get a match going by simply pressing the 1vs1 icon and then waiting for a player to accept your challenge. If not, then you can explore the open world, and you'll likely find a couple of players who are also awaiting challengers for a duel. Go ahead and join them.
This is a great way to get yourself comfortable with online play. Plus, duels are just fun anyway. So, if you'd like, start off with mano-a-mano games before heading into parties which are extra fun. But, if you feel like your single-player practice is good enough, then feel free to hop on a dance pad (yes, there are dance pads) and join a group of other fellow gamers.
Unlock new mini-games
You can play most of the games in single-player but you can't play all of them. There are a good chunk of games that are locked that are all pretty fun. There is no trick to opening them up really. Just keep playing games against other players online.
I will say that this is the only way to make the new games available. So you can't just play in the single-player mode to make this work. And that's alright, this should give you some nice motivation when playing in parties and one-on-one games.
It's always good when you can get rewarded for your play. and the game already has a deep amount of mini-games already, so to just add to it is a nice plus. And all you really need to do is keep playing. There are no real challenges required to earn new games. And the cool thing is that you might have a chance to play the new games online if other players have access to them already.
Earn some alter egos
You can get new outfits by defeating players in matches. Play in games, and get the most crowns to win. And by winning, you will be rewarded for your efforts, and that includes getting the new skins. These are called "alter egos" and feature outfit designs that might fit the persona of your favorite characters.
From a scuba diving outfit for Martiana the alien to a pirate outfit for Dukes the cat, you have your share of flair to select from once you unlock them. These unique characters are already distinctive enough, but why not crank it up a notch, right?
New looks are always some of the best ways to show how much better you've gotten at the game. All of the close games, heartbreaking losses, and heroic triumphant led to these new, stylish threads. Wear them and wear them proudly. You earned them.