Esbats are the time of greatest power and as such they are the best time for spellwork as opposed to celebration (such as Sabbats).
They are celebrated on the full moon day and you can find out when they are on my news page.
If you do not have any spellwork to do on an Esbat, just celebrate and give thanks instead. However, if you do have spellwork to do then an Esbat is the best day to do it.
Esbats also help us work out when to do spells at other times, too.
When the moon is waxing (growing towards full), then it is a good time to do spells to bring something into to life, such as money, confidence, new friends, a new job, etc.
When the moon is waning (shrinking from full), then it is time for banishing spells, such as getting rid of bad habits, anger, moving on from an ex, etc.
When the moon is new or dark (cannot be seen or only just a sliver), then it is time for a rest from spellwork and meditation. However, you can do banishings in this period if you want them to be very powerful.
So, if it's almost as Esbat, the moon is waxing. If it's just been an Esbat, then it's waning. By the way, the moon is thought to be at its most powerful in the 24hrs before it is full. So always aim to do spells before it is full - this could mean it's better for you to do it the night before.
If you just want to celebrate the Esbat, try using food. Try to eat white and/or round foods, such as pancakes, perhaps with spinach and ricotta filling, goats cheese with a fruit chutney and salad, roasted garlic risotto, white fish with rice (or even couscous), perhaps with a chilli, lemon and oil dressing. I'm sure that you can think of many more!