"Now may our God and Father himself and our Lord Jesus clear the way for us to come to you." NIV translation
Paul had learned that he could only go where God opened the door for them. He was able to listen and follow the leading of the Holy Spirit in directing his steps. We need to understand the same thing in that we cannot do anything on our own but we can do all things through Christ. We are called to follow Jesus and that means we have to listen and go where he tells us. It may be a foreign country or a simple visit to a neighbor. Either way, we must listen to the prompting of the Spirit.
"May the Lord make your love increase and overflow for each other and for everyone else, just as ours does for you." NIV translation
Paul's wish for the Thessalonian believers is quite simple and that is an increase in love. God is love and that is how His people will be made known. Paul wants them to draw closer to God so that they will love people more and that love will lead more people to accept Jesus.
"May he strengthen your hearts so that you will be blameless and holy in the presence of our God and Father when our Lord Jesus comes with all his holy ones." NIV translation
Paul's final prayer for the believers here is for God to give them strength to follow Jesus. It is not easy to be holy but that is our calling and we cannot do so on our own. Paul knew that the ability comes from God through the working of the Holy Spirit.