Omens and signs
Firstly, get Callia Underhill's great book on divination.
In that book, she explains how to create your own system of symbols
Then I was thinking about Adrian Calabrese's Sacred Signs... now, I think the book is rather stupid and not very well written, but I do believe she has a point. I do believe there are no co-incidents.
Nevertheless, whether you believe in "signs" or not, the point is to believe IN YOU.
Any reason to make up your mind is about as valid as any other reason.
They have studied people in dangerous situations, and those who survive are those who DO SOMETHING. They do what they think of doing, without analyzing and contemplating.
So, if you find tarot cards helpful in the process of making up your mind, use them.
If it helpful to believe in signs and omens, and keep your eyes open for such, do so.