Start by getting an accurate weight with the steer full (had feed and has drank plenty of water) this weight will tell you how much you need to gain. At your current weight you stated you need a 5 pound gain a day, Not impossible but not very likely either. What are you feeding how much is he getting along with a weight when he is full could help get a plan together.
If he was empty, you could se a 50 to 75 pound swing in his weight, if he eats 10 pounds of grain a feeding and drank 10 gallons of water you would see a 90 pound swing in his weight. The best thing would be to have an empty weight and a full weight to see where you really are and how to get to where you need to be.