First thing we need to state here clearly is the fact that God is the Absolute Goodness. This means that something is as good as it is somehow similar to God (that's why absolute evil doesn't and can't exist - if something exists, it is similar to God in the fact of existence, therefore at least in this it is good, so nothing that exists can be absolute evil).
God created everything to manifest His perfection, as the First Council of Vatican states it:
This one true God, by his goodness and almighty power, not with the intention of increasing his happiness, nor indeed of obtaining happiness, but **in order to manifest his perfection** by the good things which he bestows on what he creates, by an absolutely free plan, together from the beginning of time brought into being from nothing the twofold created order, that is the spiritual and the bodily, the angelic and the earthly, and thereafter the human which is, in a way, common to both since it is composed of spirit and body.
So we are all created **for** Him! Not to give Him anything, but to manifest and praise His perfection and participate in His happinness.
This brings us to conclusion, that what we really should do is to praise the Lord. With every our action and thought - if we really want it to be perfect - it needs to be directed to praise the God. Only with God as the ultimate goal of my actions can I truly love the others, really seeking their true well-being (which is salvation), and for right motives - so they can praise the Lord in Heaven!