Boke (not with an h, that's an Americanism because they can only say words how they are spelt) is not, I'm guessing, what you're looking for.
You want, I think, a non distracting out of focus background so that your subject 'pops'. Three things control this:
A. The ratio between your distance to subject, and subject distance to background. The shorter the former and longer the later the more out of focus your background will be.
B. Aperture. Larger apertures (smaller f numbers) mean less of the shot (distance wise) is in focus.
C. Background choice. A pastel uniform background will work better than a high contrast busy one.
Boke is controlled by the lens design, one lens may have a very smooth and pleasing rendition of out of focus highlights (AFS 50 mm f/1.4 G Nikkor ), another similar lens from the same manufacturer might have very harsh boke (MF & AF 50 mm f/1.8 Nikkor). Stanley Kubrick, liked to de-coat all his Nikon lenses as in his opinion it improved Boke.