"As a final note, coasting may not be the best choice in overly demanding classes or those where grading is based on objective measures, such as multiple-choice or mathematics."
I study math. Our grades are not very objective. But maybe that's because we only have oral examination and we do not have to do much arithmetic.
step 1: decide on the minimum grade you want for each class
step 2: work harder for an A than a B and likewise for a C
step 3: do the work
rinse and repeat.
oh BTW, as someone that had to grade uni students, having someone harass you for every single point on an assignment that was only going to generate 1% of your final mark does not endear you.