A wildlife photographer's case book
Badgers
Rant over.
I am lucky in being close to a badger sett, but setts are easy to spot in woodland, often on south-facing slope and especially in limestone areas, as the drainage is better.

Setts usually have multiple entrances and setts that have been around for some years can extend a long way under a wood.
The following shows a sett entrance under tree roots - these are favoured as the roots help to support the ceiling of the sett. In other sites the presence of a sett is shown by a large mound of earth underneath a large hole.

Badger paths are also very obvious in woodland, although it is only likely to be a badger path if the area is not walked by people. There may also be signs of 'rooting' where the badgers have been scratching to look for worms (their favoured food) or perhaps bulbs.
Once you have found a possible badger area, make sure the landowner does not object to your presence. Lay out a few peanuts on a regular basis close to dusk, and the badgers will soon come. A trail camera will show you if and when badgers are present, and you can lay in wait for them.

Personally I prefer not to use flash, but a battery light (such as a large LED torch) should light up the scene sufficiently, especially if you have a camera which has a high ISO range.