I learned 'em from having a States puzzle when I was a kid. It must have worked: I scored 149/150, and that was just a brainfart “duh-I knew that!” mistake from being overly hasty.
It did feel weird being asked “Where is Alaska?” and pointing to a location southwest of the 48.
143/150. Indiana was the only one which took more than two tries, though I got it on the third. And pairs like New Hampshire and Vermont, or Wyoming and Colorado, were just a random guess as to which was which.
I thought of the K-N Act too, but then I remembered that the states in that area joined the US in order westbound as the time went by. Missouri was a state first (1821), then we had the problems in Bleeding Kansas (just west of Missouri) leading to Kansas’ statehood in 1861, and just west of that, Colorado achieved statehood in 1876 (it’s called the Centennial State for a reason). Then all I need to remember is that over the top of the latter two is Nebraska.
Nebraska is north of Kansas. Nebraska is north of Kansas. Nebraska is north of Kansas. Nebraska is north of Kansas. Nebraska is north of Kansas. Nebraska is north of Kansas. Nebraska is north of Kansas. Nebraska is north of Kansas.
I remember it by Vermont being the V-shaped one, too.
My score was 150, but the only reason it was is because someone else recently linked to a game where you had to place the states on a blank map. That one was REALLY hard! But play it a few times, and it really helps you remember where they are.