The Stoics have a simple technique for making our days go better: we should think about how they could have been worse. Notice that I didn't say dwell on how they could have been worse; that would be a recipe for a miserable existence. Instead, we should allow ourselves to entertain flickering thoughts about the loss of our friends, money, lover, job, health - all the things we value.
If we do lose any of these things, we will have been prepared by our negative thinking, and this will likely lessen the blow of our loss; we will, in a sense, have seen it coming. And if we don't lose these things, we will find ourselves far more appreciative of them than would otherwise have been the case.
A life filled with people and things that we appreciate is easy to enjoy. The Stoics were smart enough to realise that we have it in our power to appreciate the life we find ourselves living if we can just bear in mind that things are a lot better than they could have been.