As a correction to what you've been reading. There is no such thing as a "Matron Goddess". Both Gods and Goddesses are referred to as "Patrons". It's a very common misconception to call them otherwise.
To begin to seek a Deity with whom to work I would suggests starting by reading the myths and legends from a variety of cultures around the world. As you read them consider whether one particular God and/or Goddess feels like someone with whom you'd like to have a relationship. I say relationship because that's what it means to have a God or Goddess as a Patron. Think of them as being parents with you as their child, that's the sort of relationship I'm talking about.
I would also suggest doing regular meditation with the goal of contacting the Gods and Goddesses. Does one come to speak to you? Do you feel drawn to one or more?
If you do find yourself drawn to a particular God or Goddess the next thing to do is to begin to work on that relationship. You might want to create an altar to the Deity on which you could leave appropriate offerings. Daily prayers to your Deities help as well. Remember that this relationship is a two-way street. You will receive benefits from them, but they will also expect benefits from you in return.
And I'd strongly suggest reading the book " Devoted To You " by Judy Harrow. The book talks at length about what it is like to have a personal relationship with a God or Goddess, how to go about building and maintaining such a relationshp etc.
And do remember that we are talking about Gods here. They are not at your beck and call. They are not spell ingredients. And they are due all the respect one would give to a powerful being.