Lifelines are simple and ARE a life saver. At least a frog saver, anyway.
When you are at a point where you know your row is perfect, thread a tapestry needle with a contrasting color yarn and slide it though all your stitches that are on the needle, while they are on the needle. If you go through the little v at the bottom of the needle, you can do several stitches at once. Leave it there until you, say, finish a pattern repeat, or approach a row that you feel gives you trouble and then you can either put in another one or pull out the first one and reinsert it.
If you need to frog, you can take your knitting off the needles and then just pull out until you get down to the lifeline and your stitches are safe. Just reinsert your needle and go.