The easiest way is to reach out to entrepreneurs that have raised before and see if they are willing to be an advisor in exchange for equity in your company. If you have something they believe in, they won't hesitate to introduce you to investors they know in exchange for equity in your company.
If you go through the advisor agreement at https://fi.co/fast you can get a sense of how much equity you should give up.
If your next questions is how to find these entrepreneurs, go to LinkedIn, TechCrunch and so forth and cold email people you find and ask them if they would interested in being an advisor.