500 yard free prep

I have a meet coming up the first weekend in May. I want to break 6:00 in the 500; first time since college. In Oct I went 6:01+. I feel good now, but if you have suggestions on how to finish/taper the work outs until then I'd really appreciate it. I'm a 49 year old male, can swim 4x a week for about an hour. Thanks, Fisch