Repairing Past Damage

So I've been thinking a lot about how the world views Christianity. I really want to be able to reach out to the people around me and share my faith with them, but I know that Christianity has a bad rep, and for good reasons. Past events (especially the Crusades and the corruption of the Church during the Renaissance) are still remembered around the world. Throughout history, "Christians" have persecuted Jews, Muslims, and various other religious groups in the name of God. More recently, right-wing conservative "Christians" have been condemning everyone around them. I actually know of churches that teach that if you don't go to their denomination, or worse yet, their particular congregation, then you are going to hell. And of course, there is always the big scandal over Catholic bishops that occured recently. The truth is, the world tends to focus on the negative, and they have a lot to choose from here.
Although I can't condemn others (because there is no way for me to truly see their hearts), I do want to help people see that Christianity isn't about hatred; it's about love. I want to show the world God's love, and that God didn't call people to persecute others but to minister to them. I want to help people physically, emotionally, and spiritually. I want to be accepting of others and show that I am willing to listen and learn. On the other hand, I can't just accept everything as true. As a Christian, there are certain beliefs that I have to stand by. There are certain thigs that I have to say are absolutes, and I have to believe in them with my whole heart. If I could believe strongly OR be accepting, my task would be easy, but I'm asked to do both. I have no idea where that line is. So I guess my question is, how do you do that? How do you compassionately stand for something? How do you make sure your words and actions remain consistent with your beliefs without unnecessarily offending people? When is it okay to offend people?