As I'm not familiar with this practice how is this a sacrifice on our part?
I understand the part of the sacrifice that Christ made....but no where in the NT do I see a requirement for us to make a sacrifice liek incense, etc, as that was already accomplished on the cross.
The best I can do is point you toward a link that outlines the Mass at which I assist: Fisheaters Order of the Mass. The right hand column gives an English translation of the Latin, that's the part you'll want to read to get a fuller understanding of exactly what it is that Catholics think they're doing.
You'll see a couple of references to incense, first "Be blessed + by Him in whose honour thou art burnt. Amen." and then later:
"Through the intercession of Blessed Michael the Archangel, standing at the right hand of the altar of incense, and of all His elect may the Lord vouchsafe to bless + this incense and to receive it in the odor of sweetness. Through Christ our Lord. Amen.
"May this incense blessed by You, arise before You, O Lord, and may Your mercy come down upon us. Let my prayer, O Lord, like incense before You; the lifting up of my hands, like the evening sacrifice. O Lord, set a watch before my mouth, a guard at the door of my lips. Let not my heart incline to the evil of engaging in deeds of wickedness.
"May the Lord enkindle in us the fire of His love and the flame of everlasting charity. Amen."
I know it's a lot to read and my wife asked "do you think they'll actually read all that?" and I knew the answer was no, but if you'll skim through it at least you'll begin to see the difference between prayers to Mary and the saints in glory and the adoration and worship of God, as Catholics understand it.