The most obvious deco elements will be the panels that you see over the ground floor windows all around the building. They will have art-deco designs in them.
The more subtle elements are the horizontal lines in brickwork "Bandings" around the building and the curve on the corner by the parking lot and street facing side. These elements lend the building a streamline deco feel. Zink/silver elements also have a deco feel. Also the "eyebrow" around the top and across the curve is a common streamline/miami deco feature.
However my one critique of the Bandings is that there should have been 3 of them together instead of 2. This would have been a bit more of an "obvious cue" to help the plebian masses "get it" ;-P One of the signature rules of thumb for deco of that sort is repeating patterns and lines in 3's. Though when I think of Tulsa Deco, especially downtown, I think of something thats a little more ornate, or dramatic, a NY type deco, not the simple Miami streamline type deco. But we do have some streamline examples in our city. And of course we have the Prarie Deco, aka the Fairgrounds Pavilion. Remember, this isnt supposed to be a deco building but one that has deco elements "pays homage to", and contemporary elements, and ties in with the brickwork in the area.

Notice the bandings in 3, and on the ballpark renderings its 2. Wish they would add one more row of bricks to give that more obvious cue to the deco.