[Q]: Which of the following solutions is better for the following goal:
how do you file your nails down?

[A]: use a nail filer, and put it against the tips of your nails. rub it back and forth on the nail to your desire.

[Q]: Which of the following solutions is better for the following goal:
How do you decide what type of fish to keep in an aquarium?

[A]: To decide what type of fish is best for your aquarium, first consider the size a species of fish will be full grown, and make sure you can safely accommodate it. Then consider things like water chemistry requirements, aggression level, tankmates and dietary needs.

[Q]: Which of the following solutions is better for the following goal:
How to trace dragonfly wing stencil onto metal.

[A]: Hold down dragonfly wing stencil on top of metal and trace around it with a permanent marker.

[Q]: Which of the following solutions is better for the following goal:
To install a CPU into a computer.

[A]:
Taking care not to bend the pins, insert it the correct way into the motherboard (triangles matching), lock it in, and install the cooler on top.