First and foremost make sure that your body is level in the water by engaging your core muscles (stomach and back) to help keep your body straight, and then look down at the bottom. Looking down is incredibly counter intuitive, as it brings your hips up towards the surface, but this will help you roll your hips and shoulders to the side – allowing you time and space to turn your chin towards your shoulder (and not lift your head, which is what your subconscious will tell you to do!).
From here, as long as you make sure that your breathing action (i.e. body roll and head turn) is smooth, you shouldn’t have too many issues. The more you snatch at the action and try to rush, the more water you’ll disturb and likely swallow.
A really good drill to practise this is side-kicking – kick on your side, with the bottom arm stretched out in front and the other arm by your side. Build up to 6 kicks to one pull (6-1-6) to build in the rhythm.
Finally, make sure you exhale properly. By breathing out under the water, all you have to do is then breathe in when you turn your head. Practise breathing out under the water when you get in – you don’t need a lungful, just enough to get through 3-4 strokes.