What should we do?

God doesn't want us to just "do good"! For the letter kills (2 Cor 3:6) and mans righteousness is like filthy rags to God (Isaiah 64:6). So what does He want? If we can't do anything to be "better," if it's all Christ's power in us (2 Cor 12:9), if we are NOTHING without Him (John 15:5), what do we have to give God? to honor Him? What could we possibly do, if even our very righteousness is like filthy rags to the Lord and if everything we do is counted as garbage (Phil 3:8)??
Well, what did Jesus do?
He didn't follow the law how the Jews thought the law was, for one. For two, He went around ministering to people. Simply loving them. Creating a relationship with them. Healing their hearts as well as their bodies.
What else did Jesus do? (For that is why He came, to show us how to live)
Jesus had a relationship with the Father. Did you catch that? Jesus had a RELATIONSHIP with God the Father. Didn't He say that the greatest commandment was to "love the Lord your God with all your heart, with all your mind, and with all your strength" (Matthew 22:37)? What would you do for someone that you loved with EVERYTHING in you?! Well, that's something to think about. Honestly, we all express our love differently. But I would write them notes, I would probably draw them things, I might give them flowers, give them a hug, listen to them... How do I give God a hug then? Well... "whatever you do for the least of these, you do for Me" (Matt. 25:40). So someone who isn't really liked by everyone, or isn't really high up on the social status, would probably be “the least of these.” You might be friends with those people; you might even feel like you're one of those people. He also said, "And whoever welcomes a child in My name welcomes Me" (Matt. 18:5).
What does God want from us? Why did He Himself willingly die on a cross for sinful humans?
Because He wants a relationship with us. He so desperately wants to get to know us, be our friend (John 15:15)! He would die for us to let that happen.
Focus on Him. Don't worry so much about "doing things right." Focus on getting to know Him; serving others in His name. The more we get to know Him, the more we are like Him, and will smell of Christ's aroma to Him (2 Cor. 2:15).
Get to know Him, He's waiting with His arms wide open :) and He'll never let you go (Deut. 31:6).