Tights are a controversial wardrobe item in many ways. [Much ado for such a little thing! ;)]
In some cultures, they count as distinctly unstylish, whilst in others, they are such a key fashion item that a whole industry is built upon designing them and shops that sell nothing but tights are a normal thing.
Women also tend to have strong opinions on them. Some will not wear them at all; some only in winter; some find tights uncomfortable or unsexy and wear stockings only; some will not wear thick tights at all but will layer several pairs of thin ones in colder weather; some like them nude only; others black only; some adore coloured or patterned tights and make these the focus points of their outfits ... the views and approaches are countless.
In accordance with their variety, making tights flattering is a complex matter too, especially so for shorter legged ladies for whom dressing their bottom halves always requires careful consideration.
The key thing to keep in mind is that legs will look longer if they blend into the rest of the look and not appear disjointed from the body. Most of the time, nude tights will be your best bet to achieve this, especially if you are showing any skin on the top half. When you choose your tights, go for as good quality as possible [to avoid the 'tights!' look] and also shine finishes [you want to blend in; shine rarely blends in].
Seethrough black tights are also an alternative, though often less stylish [compare the first two Pippa outfits with the last one]. Only wear them if some other elements in your outfit are also black.
Beware that opaque tights can look too heavy and can thus shorten legs, especially if worn with a lot of skin on show [Olivia's dress would have been much better with nude tights] or a non-black skirt [Jessica's outfit is only just about saved by the black neckline of the dress but would also have been much better with nude tights]. They are best worn with all-black or at least black-heavy outfits, when your arms and neckline are covered up.
Do not wear black tights with non-black shoes, this cuts legs off at the ankle.
Coloured tights almost never work, unless they blend with the shoes and skirt, but even so are a brave choice. Under no circumstances wear tights that do not match either your shoes or your skirt, as this is extremely unflattering.
Patterns can be OK, as long as they are tasteful [not an easy feat, I often wonder when I see what's on offer in shops!]. Make sure you keep them subtle, the same colour as the tights themselves [mainly, black or nude] and match your outfit in colour. Note in the below example how much better the more delicate pattern is, worn with an all-black outfit.
On the whole, shorter legged ladies may find it best to stick to nude tights most of the time, and to switch to [at least] slightly seethrough black ones [subtle patterns can add interest] worn with all-black outfits in cold weather.
See some celebrity examples below:
Seethrough black tights - aren't they much better when Rachel's arms are covered by the black jacket?
Olivia's black tights are all right; but nude legs would look better:
Kaley's patterned tights are actually well balanced by the all black outfit, but the non-patterned version with the covered neckline dress still works better: