1. Be worth the time and energy.
The bottom line is to be committed to the relationship. The top complaint of mentors is flaky mentees--ones who don't seem all-in on the partnership.
Don't be that guy or girl.
2. Understand that you own the relationship.
It's not your mentor's job to set the next appointment or to do the little organizing/structural things to keep the partnership going. That's on you.
3. Know what you want, and ask for what you need.
They want to provide more, not less, help. They don't want to deal with the helpless. Research is clear that the more specific an ask, the more potent the assistance offered.
4. Be prepared, personable and packed.
News flash, your mentor is a busy person. The more productive the meeting, the more they'll feel like it's time well spent.
So be fully prepared and don't be afraid to have a full agenda. And while you're at it, don't just be in advice extraction mode--be personable, be you. You can call these the three Ps.
5. Take action on the advice, run through doors opened for you.
This is the meat of the relationship, so take the advice (if you agree with it) and act on it. Then, let the mentor know you're doing so. If they open a door of opportunity for you, visibly sprint through it.