This doesn’t make sense to me, the two are opposite, so how can one contribute to the other? To be selfless means to give of yourself unconditionally, to be selfish means to only do things that benefit yourself so how can you optimize selflessness by being selfish?
You optimize selflessness by being selfish because even if you view your definitions, to be selfish means to only do things that benefit yourself. If you truly commit to what benefits oneself you optimize yourself and allow yourself to perform in all situations to the best of the individuals ability. All people are connected and will come across eachothers paths eventually. If two people decide to work together on any venture the performance output of the individuals together will be optimal (synergy). If one decides to take care of themselves they will actually be doing others favors in the process. To allow yourself to be optimal in all situations, even if being selfish will allow you to complete task to the best of your ability in all situations regardless of who the task is with. This is only one aspect of how being selfish can lead to selfless expression.
Sagittarius the Golden Child 
This doesn’t make sense to me, the two are opposite, so how can one contribute to the other? To be selfless means to give of yourself unconditionally, to be selfish means to only do things that benefit yourself so how can you optimize selflessness by being selfish?
You optimize selflessness by being selfish because even if you view your definitions, to be selfish means to only do things that benefit yourself. If you truly commit to what benefits oneself you optimize yourself and allow yourself to perform in all situations to the best of the individuals ability. All people are connected and will come across eachothers paths eventually. If two people decide to work together on any venture the performance output of the individuals together will be optimal (synergy). If one decides to take care of themselves they will actually be doing others favors in the process. To allow yourself to be optimal in all situations, even if being selfish will allow you to complete task to the best of your ability in all situations regardless of who the task is with. This is only one aspect of how being selfish can lead to selfless expression.