When I first starting sewing patterns (a wee while ago now!) the recommended thing to do was to make triangles out from the seam line, but that was fiddly cutting around the notches and depending on your cutting skills not that accurate.
Then rather than cutting around the notches, it was recommended to make snips (approx. 3mm) in the fabric to mark the notches. Some still prefer to use this method.
However, MY best little sewing friend is my water erasable pen :-) This is great on most fabrics except for the darker colours, which is when I swap to a tailor's white chalk pencil. The chalk is just as effective but requires a bit more pressure to apply the mark.
All guides and marks can be transferred from the pattern to the fabric, without worrying whether it is the right or wrong side of the material, because after a wash all marks are magically gone.
When fabric is hard to tell which is the right side and wrong side, just like the Minuro Jacket I just completed (photos coming soon), I use my water erasable pen to mark-up the right-side (out-side) of the fabric. That is, I only place markings on one side of the fabric - the side I decide will be the outside of the garment.
I love my water erasable marker and wouldn't be without it.