There are several common techniques to playing outside, that include side-stepping or side-slipping, superimposition of Coltrane changes,[1] and polytonality.
Also, outside concerns tonal tension; it does not involve breaking rhythmic, timbral or stylistic boundaries.
The term side-slipping or side-stepping has been used to describe several similar yet distinct methods of playing outside.
[3] Another technique described as sideslipping is the addition of distant ii–V relationships, such as a half-step above the original ii–V.
[4] Lastly, side-slipping can be described as playing in a scale a half-step above or below a given chord, before resolving, creating tension and release.