The origins of Sabbats where about thanking Mother Earth, Gods and Goddesses for bounty and successful crops. For example Halloween is about the pumpkins being ready to harvest. In Australia we celebrate the rituals the wrong way around so we might be mistaken in thinking pumpkins are ready to harvest in October, yet it is Autumn (May, June) when pumpkins are ready to harvest. Armed with this knowledge I know not to plant pumpkins before or during winter thinking they'd be ready by October (when in fact the crop would fail because it's too cold).
Lammas, February 2, celebrates the first harvest so this is the time we'd harvest our first crops of produce ripe and ready to be collected. Knowing this, I know this is the time to go out and gather produce from my garden. At this point in time grape leaves are ready to be harvested, ready for either preserving in brine or form making dolmades. As my vegetable garden grows into fruition I'll have more to harvest in the coming years (hopefully).
Mabon, which is coming up is the time for the second harvest. This is when fruit and produce would be harvests and pickled / preserved ready for storage over winter.
Samhain is when Halloween, of sorts, would be celebrated in Australia. This is the time the veil between the living and the dead is thinnest and we can honour ancestors and think of those who have left us.
Yule, winter solstice, is the shortest day of the year. This a time for personal renewal and honouring family and friends - we might give them a gift.
Imbolc is about new beginnings and considering the coming year, what you'll do. Life force is awakened with the first signs of green (although we don't get snow in Australia). It's a good time to spring clean and bless house and temples.
Ostara (Easter) is when flowers and life come alive, the earth reawakens, we celebrate by decorating eggs. We'd bless seeds at this time before we plant them, start new projects and celebrate the joy of being alive.
Beltane is the beginning of summer, fertility festival, we feat and celebrate with flowers and ribbons (maypole), we'd make flowering crowns and celebrate love, romance and fertility and bless crops for successful bounty.
Litha, longest day of the year, is about staying up all night (or for as long as you can or care to), leaping over bonfires to assure good crops. We bless the earth for bringing forth bounty.