The three-card spread, position by position
beginner3

The three classic positions, two alternatives that work better for specific questions and how to read the whole row instead of card by card.
You lay three cards in a row, left to right, face down, and turn them one at a time starting from the left. The most widespread assignment is past, present and tendency: the first gathers what already happened and still weighs, the second describes the moment as it stands today, the third points to where the matter is heading if nobody changes anything. That last position doesn't announce an outcome, it describes a direction.
The alternative that works best for practical questions is situation, obstacle and resource. The central card stops being a summary and starts naming what is holding things back, which is usually what you really wanted to ask. The third indicates what you have to work with to shift it. A third variation, useful when the subject is a relationship or a shared project, is what I bring, what costs me to sustain and what I'm still not looking at.
Choose the variation before shuffling and write it in your journal. If you decide after turning the cards, you will end up assigning each position whatever meaning best fits the images that came up, and the spread can no longer tell you anything you didn't already know.
When reading, resist the temptation to interpret each card separately and add up the three results. The row is read as a sentence. Look first at whether the figures face each other or turn away, whether a suit repeats, whether there are two Majors and one Minor. Three Pentacles in a row say something about the weight of material matters in the question even if none of the three cards rings a bell. A single Major between two Minors usually marks where the centre of gravity of the reading lies.
A common beginner's mistake: pulling three cards, not understanding the middle one and adding a fourth on top to clarify it. That fourth card almost never clarifies, because the problem wasn't in the card but in the question. If the central one resists, note it with a question mark and come back to it in a week with your journal in front of you.
The whole spread takes between ten and twenty minutes, and a good part of that time is looking at the pictures in silence. If you polish it off in three minutes you aren't doing something wrong, but you are probably reading the list of meanings you remember rather than the cards in front of you.