Reads, timing and bet sizing get taught as three separate skills. In practice they are one decision seen from three sides, and changing any one of them forces the other two to move. That is why a bet which looks correct on its own can still be wrong.

Each player receives two cards face down, and five community cards are dealt out across three stages. Your hand is the best five cards available from your two plus the five on the table. There are four betting rounds in a hand, and each one is a separate decision point rather than a formality.
Ace through ten, all one suit. The rarest hand in the game and the one nobody forgets.
Five cards in sequence, all one suit. The higher the top card, the stronger.
Four cards of the same rank. The fifth card acts as the kicker when two players somehow hold the same four.
Three of a kind plus a pair. It beats a flush, which is the single most misremembered fact on this list.
Five cards of one suit is a flush; five in sequence of mixed suits is a straight. Flush is the stronger of the two.
Three of a kind, then two pair, then one pair, then high card. Kickers decide most ties at this end of the list.

A read narrows what somebody can plausibly hold, based on how they have played the hand so far. It does not identify their exact two cards, and anyone who claims otherwise is guessing. Narrowing roughly, one street at a time, beats trying to be precise once at the end.
The same action taken quickly and taken slowly often means different things. A fast call usually means an easy decision; a long pause before a call usually means a close one. None of it is proof on its own, which is exactly why it has to be combined with sizing rather than read alone.
Your bet size should make sense for the hand you are representing, given what you believe the other player holds. Choose a size out of habit and it will sometimes contradict everything else you have done in the hand, which is how a technically reasonable bet still loses money.


A read gives you a range, timing tells you how comfortable they were inside it, and your sizing is the answer you give. Change one and the other two have to move. Checking that the three still fit together is most of what good decisions are made of.