One way to give more interest to your improvisations is to add enclosure tones to otherwise simple note choices. Enclosure tones are two tones which “enclose” (i.e. one higher, one lower) another note. Generally, but not always, the note which gets “enclosed” is a chord tone.
For example, if we begin with the root of a C7 chord:
…and precede the C with an D and a B:
…we have played an “enclosure” around the C.
In general, it sounds best for the lower note of the enclosure to be ½ step away from the target note, even if that means making it chromatic (i.e. not in the scale).
For example, if our target note is G (with C7 harmony) we would sharp the lower note F to make it an F#:
If we wanted to add a bit of bebop flavor to our ideas, we would play double chromatic enclosure tones, i.e. both notes would be ½ step away from the target note. One, or both notes may actually be chromatic in relation to the scale, but both will be ½ away from the target note:
To become comfortable with playing enclosures I suggest playing your daily arpeggios with enclosures around the target notes.
Expand this to include all your arpeggios (e.g. Augmented, etc.) and all possible roots. This will present you with new instrumental and mental challenges, as well as giving you a tool to use when improvising.
(If you’d like to save and print these exercises, download this PDF.)