It starts with a clean background.
The distance between your camera and your subject and the distance between your subject and the background are more important to a getting a creamy bokeh than anything else.
General rule of thumb – the distance between the two should be no less than the same.
For example, if there are 30 feet between your camera and your subject and 30 feet between your subject and your background – then you are at a minimally acceptable range to shoot at f/8 with a creamy bokeh.
Other factors are:
The closer your camera to the subject, the narrower the depth-of-field. If you can get within 10 feet of your subject, you will greatly improve your chances of getting a creamy bokeh and you will also reduce the need for more distance in the background.
Regardless of subject to camera distance, lots of distance between the subject and the background is always a good way to improve bokeh.
Let me use this portrait of a roadrunner to explain further.

Both these images are straight out of the camera. The first (above) shows the roadrunner near a clump of grass. She’s too close to the background and consequently, the background is distracting and way too busy. Our attention is drawn away from the bird.
Now let’s look at this second photo (below) which shows the same female roadrunner against a background that is 50 feet away. Note the difference. The second picture is more pleasing and has a more pleasing bokeh.

Remember the rule – as subject to camera distance decreases, so does depth-of-field. Every time. No exceptions. No matter the camera format or the lens.
I teach this all the time because it seems to be one of the harder concepts for newbies to grasp. I know this because I see their posts on camera forums about fast glass and their perceived need for super large apertures to attain a background that is out of focus. While it helps, it doesn’t matter if your aperture is f/8 or even f/11. If you’re close enough to the subject, and/or there is a reasonable distance between the subject and the background, you will get a nice bokeh.
I hope this helps.
Picture Methods has partnered with Hunt’s Photo & Video to bring you the best gear at a competitive price and backed by personal service. Call Alan Samiljan at 781-462-2383 if you need photo/video gear. If you prefer, you can also email Alan at: alansamhunts@gmail.com or just visit the Hunt’s Photo & Video Website deals page.