One mistake I have made a bit following that recipe myself, is to not lock in GOOD GAINS when they happen.
And they will happen. Just don't be too greedy.
You and I could cry over several drinks in a bar for the times that I, too, held longer than I should.
Sometimes, it happens when you just cannot be online monitoring the stock(s). That is why it's a nice strategy to exit several times to tally several gains (albeit smaller with added commissions). However, in my mind, any gain is a win.