We are again in the situation we were in yesterday: we've covered both pericopes that are in today's passage when we were in Matthew and Mark. When we talked about this passage before, I approached it from the "big picture" standpoint: that the purpose of the passage is that we should render to God what is made in His image - that is, our whole selves. Today's post will be a little more specific and practical that that big idea: as citizens of a country, we need to pay our taxes.
The big point that Jesus is making here is that we need to present ourselves to God because we are made in His image, but let's not miss the small point as well: Jesus affirms that we should pay taxes.
Christians should be known for their respect and integrity in ALL interactions, even those with the government. From Bock: "We are called to serve, to display righteousness and personal integrity in the midst of a world that is slow to acknowledge the presence of sin and moral accountability. " 
A few practical thoughts on what this means in terms of taxes:
1. Pray for our government leaders, specifically that the funds they collect will be used for good purposes.
2. Pay your taxes on time.
3. Don't complain. We live in a very privileged country and should constantly be thanking God that we are not persecuted for our faith and have an amazing amount of freedom. If you want something changed, use your freedom to do something about that change, don't just complain about it.
4. Do your taxes with integrity. Taxes are confusing. Do them honestly and to the best of your ability. Take any credits/breaks you qualify for, but the goal is not to get back the most money possible: it's to do all things with honesty and integrity. Don't lie or deceive about the money you've made, even if you know you'll never get caught.
Again, the main idea is that in EVERYTHING we should conduct ourselves as if God is our master/governor/president, because He has put all of those authorities in place. Because of this, we act honestly, even when no one is looking (Colossians 3:22).
These are just a few thoughts/suggestions. Any other thoughts or suggestions?