The truth is that it's very difficult to determine the timing of events with Tarot cards, but it's important to pay attention to the windows of opportunity. Always remember that free will affects destiny. If you're supposed to take action and you don't, you could miss the chance you were meant to have.
Also keep in mind that things don't happen until you're spiritually ready for them. If your question is “When will I meet The One?” and there are many Major Arcana cards indicating that you will meet The One soon, be prepared. If you haven't resolved other issues of your life, it may push back the timing of this meeting. It will still happen, but it will happen later.
One woman had a reading done and the psychic told her that her boyfriend would propose in the next two months. It didn't happen. Instead, they broke up. She had some intimacy issues that she needed to confront. Two years later, they met up again by chance, got back together, and he proposed. It can happen. You have to be ready in order for the good things in your life to come about.
Normally, Tarot card readings are indicating things that will happen within the next three months. But there are other indicators you can look for. Look at the last card you put down. If it's a Major Arcana card or a Court card, go backwards through the other cards you laid out until you come to a Minor Arcana card.
Then, look at that Minor Arcana card. An Ace refers to one, a Two to two, and so forth. Is it Wands, Cups, Pentacles, or Swords? Wands refer to weeks, Cups to days, Pentacles to years, and Swords to months. So, for example, Two of Wands means two weeks, and Five of Cups means five days.