how to celebrate thanksgiving day

It's hardly a "most important festival", seeing as it's only in America and Canada.

People have their own traditions. It's not a religious holiday, although people may pray.

We have turkey. These days I make it.

It is a feast day widely celebrated in the US. By and large, the meal's main dish is cooked turkey in commemoration of one of the first native foods eaten by the first English colonizers in North America. Other generally commemorated native foods eaten include the large squash, pumpkin, usually prepared and cooked in desert pies. Less generally commemorated foods eaten include sweet potatoes and prepared cranberries.

As noted by InfraBlue, these "special days" are not so much communal/community festivals, like is so often the case in Asian countries, but they are much more so family/close friends' events.

Note that he [??] called them "feast days".

Read all about it

http://en.wikipedia.org/wiki/Thanksgiving

Observed by
Canada
Liberia
Netherlands
Norfolk Island
United States

My error, thanks.

There are folks who have ham at Thanksgiving. We don't as it's not kosher. Here in New England, it's easy to get fresh cranberries so I boil them down with orange juice. It tends to be a rather carb-centric day here.

Thanksgiving, as an adult, has always been my favorite holiday of the year. Largely because of what it's NOT.

It's not a religious holiday, it's not been taken over by wanton consumerism. Sure, we may be expected to purchase supplies for a special meal, but other than that, Thanksgiving is left to its own interpretation. Not at all like Halloween, which has become IMHO, ridiculous, and Christmas and New Years, ditto.
Christmas is largely not treated as a religious holiday anymore, anyway.

For me, personally, Thanksgiving is a peaceful oasis. Because it's always on a Thursday, many people use it as a mini vacation, taking off at least Friday, as well as Thanksgiving day, and the weekend. I even tend to work a half day on the Wednesday before, leaving early to pick up last minute items for the feast, or to even go buy most of the meal, already prepared.

Again, for me, the actual day of Thanksgiving is pure quality time. I do reflect on what I'm thankful for, and if it involves another person, I tell them. Perhaps it sounds corny to some, but it is a day of peace and harmony.
Good food, good friends, good neighbors, loved ones.
The 3 days after Thanksgiving, at a leisurely pace, I do things like preparing the garden for winter, doing chores around the house, organizing pantries and drawers. Nothing rushed about it. The entire 4 days are very satisfying to me because everything happens in it's own time.

And how!

Thanksgiving is my favorite holiday too.

i was surprised canada celebrated let alone the others

but then i can be a bit of a thanksgiving

luckily my loquacious new second best friend has taken the heat off me