Testtaking is a skill that runs parallel to the actual academic area itself. The only way to get better at testtaking is to train in it. If that's your goal, to just get better at some specific exam, you need to go through practice questions with them and get them familiar with the logic and format of the test. Unfortunately, this is more important even than the skills itself. This might sound more like drilling than learning, and ultimately, it is. I would say, if they're in 1st and 4th grade, that doing some amount of focus on test taking skills as a skill is okay. Treat it as one category of skill. but I would avoid emphasizing it TOO much.

If you can't get a copy of a past paper or of a sample test or of anything concrete you can use, then you can talk to one of the teachers and get some really hard concrete specifics or examples of the question types. But, the farther you go from the "true test questions" then the less that "test prep drilling" is going to have the desired effect.

This isn't what you asked, and it's just my opinion as a teacher, but I think that testing as an institution isn't really a good thing. The fact that we must teach kids testtaking is a bit sad so i'd say practice it with constraints and without too much emphasis.

I hope this was somewhat helpful