Question

How can parallax error be avoided?

Answer 1

Whenever there is a gap between the scale and the mark to be read, parallax error is present.
a) When reading meters such as voltmeter, ammeter, etc - parallax errors can be minimized by viewing the pointer from directly above such that the pointer coincided with its image (read at perpendicular line of sight, use one eye)
(c) You may use instruments such as mirrors on the dial so that you can line up the pointer with its own reflection, to make sure that your reading is exactly at right angles to the scale.