Keys - front left, wallet - front right. No practical reason for left vs. right other than that's how I started as a kid when getting a wallet out was more prevalent than getting keys out. When wearing jeans (most days), phone goes in back pocket while not sitting and is out on desk/bar/table when sitting. For loser shorts or pants, phone goes in front right pocket with wallet when not out. Suit days, phone goes in interior coat pocket.