"How do you interpret reversed cards?"
There are various schools of thought about the meanings of reversed cards. Traditionalists say that a reversed card should always be read as the opposite of what it means upright - therefore a bad card would be considered good and vice versa.
However if you try to apply this idea you tend to start running into quite a bit of trouble with the Major Arcana - for instance what is the opposite of the Death card????? Also when using the traditional method you can often find that reversals make no sense at all in the context of the reading.
Modern Tarot readers tend not to apply the 'opposite interpretation' rule any more. Instead, if the deck was all definitely upright prior to the shuffle, and a card becomes inverted during the shuffle process, it's usually more efficient to simply regard that card as 'ill dignified' - i.e. not to be interpreted 'at its best - or worst'.
So for instance if you present the Star inverted, look hard at the cards surrounding it to see whether its terrific gift of opportunity might be blocked, or somehow delayed. Equally if you have the 10 of Swords invert, you'd feel that any apparently disastrous occurrences were nowhere near as serious as they at first appear.
So long as you start with all cards in the deck the right way round, if one is inverted on the shuffle, then I take this to mean that the usual interpetation of the card is in some way emphasised in a negative sense - not automatically the opposite, but ill-dignified. So say I was reading the 9 of Swords invert, I wouldn't see this as petty malice and spite, I'd see it as a deliberate and calculated act of cruelty (so therefore more of the usual meaning, rather than the opposite of the usual meaning). If I was reading the Ace of Cups invert then i would see this as indicating a relationship in trouble.
However I would always refer to the cards surrounding the invert one as well. I've always found it much more accurate to interpret with regard to surrounding cards than to pay too much attention to inversions. Also if, whilst shuffling the querent deliberately turned numerous cards around (like in a riffle type shuffle) I'd place much less importance on invert cards - in this case, I'd tend to ignore the negative meaning unless other cards supported it.
On a slight tangent, if you read Crowley's original definitions on the Thoth deck, a great many of them are affected by human bias (his!), tainted by his undeniably egotistical view of the World and hung about with many of the tenets and views of many members of the esoteric order, the Golden Dawn. However, the cards are also works of genius conceived and directed by one of the most experienced magickal minds of the last century. I admire Frieda Harris's artistic ability and her unique talent for translating Crowley's inner vision of the cards. This is in fact the one and only deck I have ever seen that in no way on any card jars my consciousness when I am working with it.
As you might be aware, members of the Golden Dawn do not accept the principle of reversed cards. Instead, they use working principles between given elemental forces. This is a very complex subject, but briefly it works like this:
Cups and Swords are inimical as are Wands and Disks. Therefore if for instance a good Cup is preceded or followed by Swords, the influence upon the Cup will be to slant it negatively. I do have to say however that I have not found this hard and fast rule of thumb as useful as interpreting the cards themselves.
For instance, if I were to lay down the Ace of Cups followed by the Eight of Swords, I would feel that I was looking at a new (probably romantic) relationship, which would be beset by problems in the early days. If however I laid down the Ace of Cups followed by the Six of Swords, I would feel that my querent was moving out of a difficult time into a new and more promising relationship. (As an aside, Ace of Cups, Eight of Swords could also indicate the conception of a child in difficult circumstances - you would need other cards to support this).
I hope this clarifies the subject of reversals and dignifications!