SWOT Analysis is an effective method of identifying your Strengths and Weaknesses, and to examine the Opportunities and Threats you face. Often carrying out an analysis using the SWOT framework will be enough to reveal changes which can be usefully made.
To carry out a SWOT Analysis write down answers to the following questions:

Strengths

• What are your advantages?
• What do you do well?

Consider this from your own point of view and from the point of view of the people you deal with. Don't be modest, be realistic. If you are having any difficulty with this, try writing down a list of your characteristics. Some of these will hopefully be strengths!

Weaknesses

• What could be improved?
• What is done badly?
• What should be avoided?

Again this should be considered from an internal and external basis - do other people perceive weaknesses that you don't see? Do your competitors do any better? It is best to be realistic now, and face any unpleasant truths as soon as possible.

Opportunities

• Where are the good chances facing you?
• What are the interesting trends?

Useful opportunities can come from such things as:

• Changes in technology and markets on both a broad and narrow scale
• Changes in government policy related to your field
• Changes in social patterns, population profiles, lifestyle changes, etc.
• Local Events

Threats

• What obstacles do you face?
• What is your competition doing?
• Are the required specifications for your job, products or services changing?
• Is changing technology threatening your position?
• Do you have bad debt or cash-flow problems?

Carrying out this analysis is will often be illuminating - both in terms of pointing out what needs to be done, and in putting problems into perspective.

Hearing the word 'swot' conjures images of Just William, silly uniforms, grumpy teachers and girls in pigtails.

A swot is a person who devotes a lot of time to studying, but it doesn't have the same connotations as a nerd. Rather, a swot normally has low confidence, and learns things by rote. The swot may be the person who gets the best marks in the exam, but you know she had to work for them.

The word 'swot' started off as 19th Century military slang. 'swot' is a variant of sweat. One theory even claims that is was at Sandhurst that the professor of Maths, one William Wallace, first used the expression "It mades one swot", and the word caught on from there. Certainly, in 1850, soldiers used the word to mean mathematics. It then extended to the people who studied it, and from there to people studying in general.

Swot is also a verb. To swot up is to study, often a specific subject for a specific purpose. Swotting up before an exam or interview is common. The 'up' can be dropped, but its usually there.

'Swot' is generally considered an insult, or at least not something anyone would want to be. The image of the unpopular school swot, alone with his books and ignoring the world, was reinforced by children's books of the first part of the 20th Century, as well as comics like the Beano and the Dandy. Swotting up, though, is quite acceptable, as it's a bit like cramming, and implies the swotter has left everything to the last moment.

Perhaps because it originated as a spoken word, swat is sometimes used as a variant spelling. While used universally throughout Britain, as well as in South African English. It's used in Australia and NZ, but not commonly, and mainly the verb form. In Ireland, they tend to spell it 'swat'. I suspect that Americans don't use it at all.
(not sure about Canada; let me know).

cf. The Oxford English Dictionary
Thanks to CloudStrife, StrawberryFrog, sneff, and Mogest.