How to receive power

Most of us desire to become more efficient in sharing our faith with unbelievers, but some time we don't know how to become efficient
The key is TO BE FILLED with the HOLY SPIRIT
- How can I be filled with the Holy Spirit ?
- How do I know that I am filled with the holy spirit ?
- What I am going to do then ?
- Is there a specific technic that will allow me to be a more efficient and power clothed witness to Christ ?