Short video showing how to boost achievement for "Too Many Cooks?" do exactly as in video until achievement pops.
WARNING: Selecting another panel other than what is seen in video will make the option disappear to complete to community goal repeatedly.
So Steps to do this is as follows:
1. Go to a station, Start port services, Mission board.
2. Select community goal tab, then select an achievable community goal i.e. for an example deliver hydrogen fuel to a particular station or choose another i.e. kill ships in certain system to claim bounties.
3. Go deliver at least 1 ton of the said so item or kill 1 enemy and claim it in the station required.
4. Wait till community goal finishes on Thursday.
5. Go to station the community goal was previously held at to claim reward.
6. Star port services, Mission board and then claim reward by selecting complete.
7. Back out to Start port services and then Commodities market.
8. Back out again to Star port services, Mission board and then claim reward again by selecting complete.
9. repeat steps 6 - 8 until achievement pops.
Have fun.
NOTE: Only the initial complete gives you an actual credit reward and the rest only work for achievement progression.
Credit to CMDR Realitybitesdog for providing me a video for this.