For the most part, there is no way to predetermine the quality of a lens's bokeh simply by looking at its construction, and even if you look at sample images you may be flummoxed, because the quality of the bokeh can change with the aperture setting as well as with the subject and background distances.

For example, the whole "number of blades" thing where folks run down how the EF 50/1.8 II is crappy and gives you pentagon out-of-focus highlights because it only has five blades, and not those nice smooth circular blobs is only true at specific aperture settings and distances. You can easily get circular out of focus highlights with an EF 50/1.8 II if you avoid them.

Bokeh C/A (aka purple fringe, or longitudinal chromatic aberration) can also disappear once you stop a lens down.

Double-ringed, or harsh bokeh may only happen at given subject distances, while the same lens at a different distance or setting may give you creamy smooth bokeh. See: http://neilvn.com/tangents/bokeh-vs-shallow-depth-of-field/ which has an example of harsh bokeh shot with a 50/1.4D. The same lens with which Nikon boasts about "beautiful background blur" on their website and posts these sample images).

We know that swirly bokeh shows up in Petzval lenses because they don't correct for field curvature, but most folks don't want swirly bokeh and most modern lenses do correct for field curvature. :) And, of course, lenses with extremely large max. apertures (f/1.2 or larger) can exhibit catseye bokeh when used wide open due to optical vignetting. But it's not like you can avoid that.

Generally speaking, the more experienced you are with lenses, the more you realize that to really learn a lens's bokeh, you have to use the lens. Perhaps the only thing in a lens's specs, if it's there, that might guide you to some general idea of a lens's bokeh characteristics is to look at the MTF chart and see how close together the meridonial and sagital lines are to each other. The closer they get, the smoother the bokeh will be.

That's pretty much it.