Diesel Bombers - Just got 6.5 Suburban

Hi, I just recently acquired a 99 Suburban with a 6.5 turbo. It has a lot of kms on it, yes, kms, I'm from Alberta, Canada. It is currently sitting at 460,000 kms. I've never owned one of these, I had a duramax a while ago, and really liked that one. I've heard in the past that the non turbo 6.5s were nothing short of amazing for fuel mileage. Any suggestions on how to get optimum mileage on something like this? I am doing first oil change and going to delvac 5w40 oil. Open to suggestions and comments, thanks for having me here, looks like a pretty good forum. I am a mechanic, done a fair bit of work on Fords (other people's trucks). Dale