What reversed cards actually mean
The most over-dramatised part of tarot, and the easiest to get right once you stop treating a reversal as bad news.
A reversal is a dimmer switch, not an inverter
The most useful way to read a reversed card is as the same energy, held up. Something is in the way of it, or it is turned inward instead of outward, or it is present and not landing. The Ace of Cups reversed is not the absence of love; it is love that is not being expressed.
Some reversals are good news
The Devil reversed is a hold loosening. The Ten of Swords reversed is getting up. The Eight of Swords reversed is seeing the gap between the swords. Reading every reversal as a negative means missing the cards where the reversal is the best part of the spread.
How many is too many
A real shuffle reverses about half the deck. Most readers run far fewer than that, because a five card spread with four reversals reads as unrelieved bad news and stops being useful. This site runs at about three in ten, which is a compromise rather than a rule.
You are allowed to not use them
Plenty of good readers do not. If reversals make your readings worse rather than richer, shuffle without them and read the position and the surrounding cards for the nuance instead. The deck does not mind.