One of the simplest approaches to soloing is to come up with a good riff and then alter it to fit the chord changes. This works particularly well for instrumental tunes.
Here is an example of a riff style solo from the playing of Albert Collins, a master of understatement. The solo contains three riffs, each 12 bars long. The first riff uses only one note and leaves space for call and response with the other instruments.
Here is another riff which leaves room for call and response with other instruments.