Most Christians spend little or no time reading or studying the Word of God. The danger in this, is that satan can tell you anything, and you cannot refute what he says, because you don't know what is in the Word.
Another problem with not reading the Word, is, you don't know what responsibilities and blessings you have. When you don't read the Word, you start to lose your relationship with God, and miss out on most of the good stuff.
In the above verse, Jesus gave us authority over everything in the spiritual world, except people. Let me explain briefly.
If someone is sick, you proclaim your authority over the spirit of that sickness and rebuke it in Jesus name, telling it to leave. Then take authority over that sickness and proclaim it healed in Jesus name while laying hands on that person.
Remember, you need faith in Jesus, in order for you or someone else to receive what Jesus has already done. For instance by His stripes we were healed. It is not necessary to pray for healing, it is just necessary to proclaim healing in order to receive what is already there. It is not your power but Jesus who did it and is making it manifest. He did however give you the authority to act in His name in order for whatever you are praying for to manifest.
There are many books about the authority, and they all go into detailed explanations. Kenneth E Hagan wrote, and made CDs, even DVDs. You can find them@Amazon.com. Have a blessed day. Praise the Lord!
Remember Jesus Loves You
Prayer of Salvation
Lord Jesus, I thank you for what you did on the cross for me. Your blood washed away all my sins, by your stripes I was healed, your death and resurrection brought me salvation. Please forgive my sins, and come into my heart as my personal Savior.
Thank You Lord