You know that you need to surround yourself with amazing people. People who support you, who act as a sounding board and who challenge you. One important place where you want to gather these people is on your (advisory) board.
The common mistake I see entrepreneurs make is selecting their board based on some random criteria (which often is “how good does it look/make me feel to have this person associated with my company”).
The way you want to approach this is much more strategic: Ask yourself what you need, then find the best possible person to help you. Write a job spec for each advisor, then fill this position just like you would fill any other open position in your company.
Say, for example, your company builds a consumer mobile app. You identify the need for a strong user experience. With the need identified you write your “job spec” for the ideal advisor, create a long list of potential candidates and start reaching out to them. When talking to your potential future advisor make it utterly clear why you want them on your board, what the expected commitment from your advisor is (e.g. one hour of feedback per month plus introductions to people in your advisor’s network as appropriate) and what’s in it for them.
And lastly: The onus is on you to manage the relationship. You have to set up the calls; you have to follow up; you have to make life as easy as possible for your advisor. Simply treat them like the messiah!
Now: Go, figure out what and whom you need and surround your company with amazing advisors!