1. Think about it.
2. Get super hyped.
3. Tell everyone.
4. Go to step 1.
5. Plan it
6. Execute
7. Profit.

Or as the great James Acaster said (regarding making flapjacks):
1) Start doing it
2) Have a break down
3)...Bon appetit

Your mistake is step 3. Telling everyone should be after execution.

Telling everyone before you'd done it gives you a sense of accomplishment when people pat you on the back, and now you have little to no reason/motivation to actually do it.

Yes, I read that in some book, but I also believe it.

always stuck at 5. xD