There are various ways to run an apple (or orchard) wassail, but here are the key elements required:
An orchard (especially apples)
A date in January: traditionally Twelfth Night (5 or 6 January) or Old Twelfth Night ("Old Twelvey", 17 January) but it doesn't matter too much
Warm clothes (optional nature and apple theme)
A torch or lantern
Cider or apple juice (add honey, spices and heat for a wassail drink)
Something to bang or make a noise, to ward of any evil spirits and wake the trees from their winter slumber
Your voice, to serenade the trees (you don't have to sing if you don't want to) and encourage a good harvest. See Island Wassail History for a wassail song to sing.
Someone (e.g. a local Morris side) to lead festivities and dance!
Get in touch if you want suggestions or help finding people wightwassail@gmail.com