Timing exercise

I think you would benefit from a timing exercise,It is learning about how long one minute is without looking at a watch or stopwatch. If you don't have one already, buy yourself a stopwatch with lap timing capability. When you go to do a set of problems, start the stopwatch but turn it over so you can't see the time. Every time you think one minute has gone by, push the lap button. When you're done, see how good you were - and whether you tend to over or underestimate. Get yourself to the point where you're within 15 seconds either way on a regular basis (that is, you can generally predict between 45 sec and 1min 15 sec).

Now, how do you use that when doing problems? If you're not on track by one minute, make an educated guess and move on. (The general idea is that if you're not on track by the halfway mark, you're unlikely to figure out what's holding you back AND have time to do the whole problem in the 1 min you have left.) For SC, if you're at the one minute mark and you've dealt with everything that you definitely know how to deal with, pick something from among the remaining choices and move on.

Remind yourself that you only need to get about 60% of the questions right. It's okay to get this question wrong - if the question's driving you crazy, forget it!