Add punctuation: Managing your files with WordPress has never been easier
A: Managing your files with WordPress has never been easier.

Add punctuation: We are up against big American corporations with plenty of capital and yet we have still managed to develop a better product
A: We are up against big American corporations with plenty of capital, and yet we have still managed to develop a better product.

Add punctuation: It shows that world leaders believe that education is of great importance not just for the individual world citizen but for the international community as such if we are to achieve a more positive and more sustainable development leading to a better societal development
A:
It shows that world leaders believe that education is of great importance not just for the individual world citizen but for the international community as such if we are to achieve a more positive and more sustainable development leading to a better societal development.