One of the most common problems for people when they start crocheting is loosing stitches on the edges. This is really easy to do (honestly no matter what your skill level is) because the turning chain kind of gets lost and does not look like a stitch when you return to that spot. Some patterns are particularry hard to identify where the turning stitch is.
I made this swatch to help someone else on this issue. The swatch is made from SC clusters which can be found in this sweater pattern Twila. for this one you chain 1 at the end and 2 at the start of the next row (so chain 3) this chain get's lost though once you start to work into the stitches.
To make sure you won't be loosing stitches, no matter what the pattern, you will need 2 markers. I often prefer paperclips (or piece of contrasting waste yarn works fine as well). Place your marker in your top chain you just made before you start to work your row. When you get to the end of the row you will place your hook into the stitch which you placed your marker in the beginning of the previous row and than remove the marker, chain up and place the marker back into the last chain of your turning chain.
Repeat these steps and you will be sure to not loose stitches on your edges due to not seeing the turning chain.
This works for any stitch pattern, even if you are doing plain single crochet of double crochet.