You can usually find a skip level in every map. The proper time to use it, assuming you are not playing multiple levels simultaneously, is after you complete a map, but before you return to the map menu. Assuming the next map is still locked, if you use the skip level while playing a map, the next level is unlocked but the victory gains you no additional level. If, instead, you wait to use the power AFTER the victory, the next level is unlocked by the victory and the one after that is unlocked by the power. If course, if you return to the map menu, it's too late to use any power (although I guess you can start the next map, use the power, and then quit the current level. This will cost you the power if you had 5. However, if you used the power before leaving the previous map and then claimed the unused power, you will end up with 5 instead of 4. With fewer than 5, both methods work out the same.). Bottom line - playing a skip level power in an uncompleted map that you intend to finish is always a losing move

Edited 1/17/2023 20:59:50

At phase 3 you can unlock skip level. This will really rush you through the idle maps.

Also I heard that USA and Trisk are two maps that are recommended to skip the first time.

I skipped Trisk the first time but USA was a fun map to complete. The only problems I ran into were selecting counties around NYC (too close together and enlarging the map also enlarged the text (occupied armies) so you couldn't see the boundaries) and a county in Virginia with 299 billion armies. This I defeated with an inspire mercenaries power (to get the 20% needed) and the epic triple strike card I won playing a hardened map. Needless to say, without that card, completing the level would have been impossible. Now that I'm in my second pass through the maps, and just opened phase 3, I'm planning on tackling both trisk and hardened trisk. Perhaps I can raise the triple strike card another level first so instead of needing 20% to use it, it will return 60% instead.

Edited 1/23/2023 03:18:52

@Mark is right. The legendary triple strike artifact makes all the difference. Then the big stack territories actually benefit you by generating 60%. There is one of these on Trisk, USA and Europe. An easy way to find it is to look at the values of the bonuses. The bonus value is calculated by the cost of the territories within it. So when you see a bonus that is worth way more money than those around it, you know there is an expensive territory in it.