How did you do it? Just let him/her cry when he wakes up at night? For how long?

LO is 7.5 months and has gone through phases of going without night feedings. He's been sick off and on for a few months so I have put off any sort of sleep training. But I work 40 hours a week and the night wakings are getting old, fast. So, I think we're going to try to eliminate his night feeding soon.

How did you go about it?