Once you have all of the basics in terms of scales, intervals and arpeggios, you have the foundation for building your improvised lines. The next question that comes up with most students is "Where do I go from here?" The next few articles will cover several different paths to try.
When the listener becomes involved in your solo, they are playing an unconscious game trying to guess what comes next. If they are right all of the time, they will stop listening, feeling that you are too predictable. If they are wrong all of the time, they will stop listening, feeling that what you are playing makes no sense to them at all.
The challenge then is to give the listener enough that they can "guess right" some of the time, while still giving them enough surprises to keep them listening. One way to do this is through the use of motifs. Simply put, a motif is a theme that is repeated either several times in a row, spread out over the course of the solo, or both. This gives the listener a familiar "hook" that they can recognize from time to time to "keep them in the game" in between the passages that are not familiar.
There are two basic types of motifs. The first is the rhythmic motif, which consists of taking any rhythmic pattern, and repeating it. For instance, take a simple pattern like four eights, a quarter and two eighths in 4/4 time. You use this rhythm either to repeat the same note or a sequence of different notes. The idea is to give the listener a repeated pattern so that they feel they have heard the idea before. You can return to it at any point in your solo, or repeat it with different notes sequentially.
The second type of motif is the melodic motif. In this case you repeat a melodic sequence to give the sense of familiarity to the listener. An example would be to play your first note, go up an interval of a third, and go back down in seconds to your starting note. This type of motif can be spread out or compressed using any rhythm you may choose, so unlike the rhythmic motif, it is not limited to the same duration of time for each repetition. This one is usually harder to do "on the fly" than the rhythmic motif.
Both can be combined together using the same rhythm for each repetition of the melodic motif. Listen to Beethoven’s Fifth Symphony as an example of how you can apply this kind of thinking. You can repeat the melodic motif and keep lengthening or shortening the rhythmic motif as is done in that symphony. Listen to how others in all musical styles apply this thinking, and look for this kind of thing whenever you listen to anyone else. This is a good basic jumping off point for starting to develop more "listenable" lines.
I wish you all the best for the Holidays, and hope that you all have a great New Year. If you have any questions or would like to see a particular topic covered, contact me.