To get God's attention, should not be the question, since God has His eye on us from birth. Whether we accept Jesus as Savior or not God will judge us. All our actions, thoughts, and words will be brought to light, and we will be judged accordingly. If we have our name written in the Lambs book of life then we will enter the glories of heaven, not because we are perfect, but because our sins are covered by the blood of Christ, if not then the person will be cast into the lake of fire. The question is, "How does God get our attention?"
What does God have to do to get us to recognize His presence, and sovereignty? He has already given us a written history of His actions in the bible. There are many examples of His work with the faithful who listened to the voice of God. We are presented with how Abraham was called to go forth from his home and become the father of a nation, of how Moses was saved from the very people who eventually called him a prince, and became a savior to the very nation he was born into, who where in slavery. We have the history of how this same band of slaves entered a land that God said He was going to give them, to grow and be a witness to His glory. There is the account of how a shepherd boy became king, because he trusted in God. There is the history of how this same nation turned their back on God and worshipped false gods, and how they were conquered and then in captivity turned back to God and where delivered and went back to their country.
In the New Testament, we find the fulfillment of the prophecies found in the Old Testament. The birth of the promised Messiah. His birth, death, and resurrection where all prophesied and completed. The life of Jesus has been witnessed and written about extensively, and cannot be disputed. This same book tells how the nation of Israel would be dispersed throughout the world, then God would bring His people back to their land that He gave to their fathers, and this occurred in 1948 when Israel became a nation again and the Jews started going home. The flogging and crucifixion of Jesus should be all that is needed to get the attention of any person, but needless to say, the message is not accepted by all.
We have the story of Paul, who was a very well educated rabbi persecuting the Christians, who had Gods attention. When the time was right God got Paul's attention with a blinding light, and from that point on Paul was the missionary to the gentiles and spread the gospel all the way