With my way of doing things I would say first I'd look to myself.
First what do I mean by ancestor spirits. Broadly this would be those that came before you, or the spirits that made you who you are. This could mean the spirits that shaped the land you think of as home. It could be the family that passed their blood down to you. Or the people and lands they came from. Further still this could be folk you don't share blood with, but influenced you or your family to where they are now. Two examples of this for me would be, a step-father of mine that lived just long enough to share his blood with the family and give us a strong and prized child. Another was a great man that helped me become who am. He became part of my ancestry purely through his actions and teaching his wisdom.
So, for me it would greatly help to determine direction by knowing just who it is I'm trying to connect with.
I would also ask myself why I wished to connect with them. Maybe its something I feel I should do. It could be I think it is the next logical step in progress for myself. Or I hear others sharing their experiences and I wish to find that for myself. On the other hand I could be trying to find stability and connection to the world and myself. No mater what the answer is it often helps me to gather will and intent if I'm clear with myself on what I'm going to do and why.
More practically I would say I would look to my strengths to see how they can relate to what I want to accomplish. If spells are a strong suit then I would go there. If not maybe energy work, or meditation. I also use study in connecting with my ancestors. Genealogy, the histories of our people, and learning about the places they lived and things going on around them, for me this can give common ground to connect on when its time to work. I also have one family member that connects very strongly through celebration during holidays for our ancestors. Again these connections can be half the work.
Now, these things go to the way I work, and we all do things a bit differently. So, I would say put some real time and effort into deciding what feels right to you and how you go about this sort of thing.