Start with your two end posts on a straight run, and then put a line up (1 ft off the ground) between each posts. This is your fencing line.
For stock fencing on soft ground, make sure you pack some stones around your strainer and use a footer (3” x 3” x 12”) attached to the bottom of your strainer horizontally (about 10” from the foot end).
Once your strainer is in, place a box of matches on the top of the post on it’s end and “wack” the top of the post with the back of a crow bar. If the matches fall over, your strainer is not strong enough for high tensile wire, properly strained.
Never bang your staples in all the way on intermediate posts. Wire needs to expand and shrink as the temperature changes!