1. There are 4 different modes that are offered: Classic Mode, Daily Challenges, Events, and the Star Club. Any game that you play in these modes will contribute XP to that game you play. Enough XP will result in you leveling up.
2. XP offered increases as the difficulty increases. In classic mode, XP ranges from 300 (Easy) to 6000 (Grandmaster). There are no Master or Grandmaster difficulties for FreeCell. Also, in the case of Pyramid and TriPeaks, the number of boards you clear will affect the amount of XP offered. For the other 3 modes, XP ranges from 300 (Easy) to 2000 (Expert).
3. Bonus XP doubles the amount of XP that is usually offered for a game or mode that the XP is offered. Thus, XP offered can range from 600 (Easy) to 12000 (Grandmaster). There are times where Bonus XP can be offered on everything (all four modes and the games in them). For instance, Bonus XP is offered on everything Solitaire Day (May 22) and possibly the entire week of the day. There was only one instance where XP was tripled and this was on May 31, 2020. No, I did not take advantage and of course, the DLC was not offered then.
The absolute fastest way of getting this achievement is by doing the following steps:
1. In Classic Mode, tackle the games on the highest difficulties that are offered. You will get most of your XP that way. As the games have their own modes themselves, you can select modes that you can handle (Draw 1 Klondike, 1 Suit Spider, etc.).
2. Take advantage of Bonus XP opportunities. These can come in two ways. The first way is where the game in Classic Mode gets Bonus XP. That means that each difficulty gets double XP and all the games of that kind in the Daily Challenges and the Star Club get Bonus XP as well. For instance, if there is Bonus XP for TriPeaks, all the TriPeaks games in Classic Mode, Daily Challenges and the Star Club will get Bonus XP. Almost always, there is an event dedicated to the that game (such as TriPeaks mini). The second way is that a particular mode can get Bonus XP. This means that all the games in that mode gets Bonus XP. For example, if Bonus XP is offered in Daily Challenges, all undone Daily Challenges will get Bonus XP.
3. Try revisiting older challenges. If you have completed Daily Challenges and Star Club challenges in earlier versions of Microsoft Solitaire Collection (Version 3.18 and earlier, see lengthy post here: Synchronization between Win8.1/WP8.1/Win10/Win10M Versions), they will still have XP available. While it is helpful to revisit them and redo them for the XP, it is advisable that you wait until Bonus XP is awarded so that you get "double for your trouble." If you have a premium sub, that is even better where revisiting old daily challenges are concerned.
So there you have it. So many opportunities. Good luck.
