If I were to start over the first 10 things I would do would be
1. Make a Flag to find the wind direction.
2. Make a Building hammer and expand the raft.
3. Make a sail and find some islands.
4. Craft the simple water purifier and grill.
5. Craft the Research table a try to get the smelter as fast as possible.
6. Make a permanent anchor.
7. Build the advanced water purifier and grill.
8. Build a tree farm.
9. Craft a Metal Spear.
10. Create the antenna and radio station.
The Most useful tool I have:
My Raft (current date):
And the best feature on it would be this cat: