“You, who dwell in the gardens with friends in attendance, let me hear your voice.” (Song of Songs 8:13)
Our godly ancestors thought of the Song of Songs as the central book of the Bible because it speaks of the intimate relationship between Solomon and his bride, a picture of the relationship that Jesus seeks with each of us and all of us, His bride, the Church, today. And here in this verse we see the Bridegroom's last words before He leaves her...very evocative of the last words at the end of Revelation. Last words are very important in such a relationship. “Let me hear your voice.” So the first thing to remember as we start to pray is that God is longing to hear us. We don't have to persuade Him to listen; He has been waiting for us to spend time with Him.
It is also helpful to look at Luke 18 - The parable of the persistent widow. Of all the Gospel writers, Luke seems to speak more of prayer than the others. When Jesus went up the mountain, it is he that tells us that He went to pray. Luke includes two main passages of Jesus' teaching about prayer (the other being Luke 11) and here it seems that Jesus is so keen that we should understand that very unusually He even tells us the point of the story right at the beginning! “Then Jesus told his disciples a parable to show them that they should always pray and not give up.”
In the story there are three characters...God (portrayed in this story as unjust, grumpy, unhelpful, presumably to make the point that, as God is not like that, the adversary, Satan, must be even more active than the adversary in the story), a widow and her adversary. So, there are three people involved in prayer. God who is longing to hear us and doesn't need persuading; our, and His, adversary Satan who fights all the way; and us, seeking to pray according to God's will but being hindered by Satan. Hence the vital importance of persistence.
It is said that Sir Winston Churchill preaching at his old school restricted his sermon to one thought repeated three times. “Young men” he said, ”Never give up. Never give up. NEVER give up.” My friend, who was a boy in the chapel at the time, said it was the only sermon he remembers from his five years there!