If I don't believe in Jesus, can I still pray to God?
Jesus and God are one. It is impossible to pray to God and not be praying to Jesus as well. However, if you do not believe in Jesus, you have no access to God, the Father. In John 14:6, Jesus clearly says that, "I am the way and the truth and the life. No one comes to the Father except through me."
The first prayer that God hears and answers is the prayer to receive salvation and forgiveness. Once that relationship is established, the doors are open for constant communication through prayer. "He shall call upon me and I will answer him: I will be with him in trouble; I will deliver him, and honor him" (Psalm 91:15); "And it shall come to pass that before they call, I will answer; and while they are yet speaking, I will hear" (Isaiah 65:24); "Ask and it will be given to you; seek
and you will find; knock and the door will be opened to you" (Matthew 7:7).