The Assassins of Fortitude
If you look at the parts per min on the top 512 clans you will see the leaderboards are not worth looking at. Just compare yourself to the ones around your own level/ your friends.
If you make sure you leave the easier to complete missions for the weeks that have risk of population and do other missions for population gains and earn as many parts/supplies in each game you will see your clan start to grow. Healing or gifting are probably the easiest of the missions.