How to manage the end of the row.

You most definitely need to follow your directions on your pattern.

But, there is a small trick to getting your edges right.
Ready for the big secret?

Make sure you do your last stitch in the turning chain or stitch of the last row.  Many people forget that very last stitch. 
You will know if you are missing it.  The number of stitches will decrease each row.  Or, if you are adding to many to the end, you'll have extra stitches.

Just keep an eye out, and make sure you get your last stitch.