Pray without ceasing could simply mean that we have constant contact with the Lord that we don’t have any trouble talking with Him whenever someone we know has a special need. Perhaps even special needs of the world.
The next verse speaks of giving thanks in everything. Here we are told that this is the will of God in Christ Jesus for you. When I look at the world and this peaceful spot God has chosen for me to live why can’t I give thanks? Quenching the Spirit could have many facets. If I have a gift (and we all do) and don’t use it I am quenching the Spirit. If we limit our spiritual exercise to the four walls of the church we are quenching the Spirit.
To abstain from every form and even the appearance of evil is very important.