We are sorry to hear of your difficulties.
Chazal tell us, as your rabbi said, that sincerely praying for someone else will send an answer for our own prayers. This principle applies even when we pray only for one person, so a full list is unnecessary.
Thinking a bit about the circle of people you know should bring up a few names of couples who are seeking a first child, or perhaps struggling to add to their family, or of people seeking a life partner. Perhaps you could share other kindnesses with them aside from prayer as well.
Spiritually, performing acts of kindness (chesed, charity, giving of your own time and means) is as important as praying for others. Immersing oneself in giving is a powerful way of dealing with one’s spiritual needs, and divert attention from one’s own problems.
Though praying for others can make a difference, please do not neglect to pray for yourself and ask God for what you need. You may also find it helpful to become involved with a support group for religious couples experiencing infertility. Please check our list of Fertility Resources for organizations that can help.
If you are not seeking medical attention, and you have been trying to conceive for over a year (over six months if you’re over 35), we strongly suggest you explore this possibility. There is no contradiction between effort on a spiritual level and efforts on a practical level to the extent possible. On the contrary, these two actions should always complement each other. If you need advice on how to get started, please send us more information about the type of problem you are experiencing.
You may also find it helpful to schedule a consultation with a Yoetzet Halacha Fertility Counselor. (This is a free service. Details here.)
We wish you much hatzlacha, may you find yourself in a healthy pregnancy soon!