How can I be sure if God is guiding me? How can I read the ‘road signs’ of life? Are there any clues in the Bible? 

I think so. And they are important to know, not just for individuals, but for churches as well. Acts 16:6-10 is the account of Paul on his second missionary journey. He lays travel plans but on two occasions he is prevented from sticking to the proposed itinerary (talk about “detours”). The providence of God is obvious. Being hindered to do what he wants, Paul is open to changing direction so as to be able to be in the place God has in mind. After a time of uncertainty, God makes clear the new direction. 

It is right to make plans and have goals. But those plans must be submitted to the will of God and be open to his veto. Three verses help us here: 

Romans 8:14  Those who are led by the Spirit of God are sons of God. 

Proverbs 16:9  In his heart a man plans his course, but the Lord determines his steps. 

James 4: 13-15  Now listen, you who say, “Today or tomorrow we will go to this or that city, spend a year there, carry on business and make money.” Why, you do not even know what will happen tomorrow. Instead you ought to say, “If it is the Lord’s will, we will live and do this or that.” 

Of course, believing that God leads is one thing. Hearing/noticing his leading is another!