Having a relationship with God is much like having a relationship with any person. God is, after all, a person. Granted, He is a Divine Person, but He is someone with Whom to be in a relationship just the same.
All relationships develop. Even as an infant, to a certain extent, one must learn who Dad is. This happens by spending time together talking, playing, eating, learning what each likes - the gamut of what it is to be in a close relationship with another person.
How does one apply this to God? It is no secret. You spend time together, we are invited into each other’s activities, we learn about Him, talk with Him, do the things that He likes to do, etc. In other words, don’t treat Him as though He were merely a force, an emergency dispatch Person, some distant being or only an historical figure. He is alive and active all around you, calling you at every moment, desirous of you, shouting out for you, wanting to walk with you and be consciously with you.
BUT - if you don’t know how to do this - even if you pray every day - how do you get started? Get started like you would with anybody that you want to get to know but can’t quite figure out how to fit into each other’s lives yet. Start by holy flirting. Whenever or wherever you come across Him, smile and send a hello - like a quick text. If you are in a deadly meeting and God comes to mind, don’t think, “Gee, I’ll have to pray later,” send him a text prayer immediately. “Hello God. Me here. Bored. Thinking of you.”
Make a surprise visit to His house. Pop in for just a moment. “Hey God. It’s me! I was in the neighborhood and thought I’d pop in and say hi.”
Open yourself up to a message from Him. Make yourself available. “Okay God, what do you want me to learn, understand or do today? Who do you want me to meet? Send me someone to do something for today.”
Spy on God. Read a little of His history (Scripture.) I bet His mom would just love for you to read about her Son since they didn’t have photo albums back them. When you start, it doesn’t have to be an hour sloshing through the genealogy. Take 5 minutes and pick a verse.
Also get to know His friends and find out more about Him through them. The saints have all kinds and various insights into Him.
All relationships are two way streets. It won’t be all God. He respects you too much. He is like the Good Neighbor Who sends cookies over to your house and sits out on His front porch and calls out, “Hello!” and invites you over dinner. “Come on over! I’d love to have you for dinner anytime! There is always a place at the table for you whenever.” We just have to stop a frantic life, walk up to the railing of the porch and choose to set the date.