To have a strong relationship with God your relationship with God must be the most important thing in your life.
To be saved you need to repent of your sins, accept what Jesus did on the cross as payment for those sins, and you need to accept Jesus as Lord. It's not enough to know he died for you. Salvation is a gift that you must consciously accept or you don't have it.
Once you're saved you need to pray regularly, read the Bible regularly, go to church regularly, and grow in obedience. You can pray using the ACTS model of adoration, confession, thanksgiving, and supplication. It's important that you talk to God. Don't just recite the prayers of others. Name your sins and confess them. Don't just say, "I confess my sins." That's worthless. You should praise God for who he is and thank God for what he's done.