I like your answers, they both make a lot of sense. Especially regarding timing, I was looking at it in a more linear and compartmentalized approach
I guess yeah the key is practice ! And breaking the problem into clear small bits, what's given, what's wanted
Often what's wanted is a rule or a concept, so I MUST know that at least, and be able to tell that this is the rule/concept needed here, that's step one
And what's given is number, variables, values whatever
Crossing the chasm and closing the gap to get all the numbers for the rule, often this is the tricky part, seems from the practice problems I've done is that usually they try disguising the given so it doesn't at first impression fit into the concept directly
Other challanging questions are like you said, multiple concepts and strategies meshed into one
And the third kind of challenging questions are those with complex wordings, which often translate to complex relationships among the variables
I think like you said, in all three cases, practice is key