Let me say two things up front.
Firstly, I love the word swooshery and can spend literally hours by the coast pointing my camera at all manner of swoosh. Secondly, I don't believe there actually is a 'right level' of swooshery. As like most (all?) photography I believe the right level is actually very subjective and should be personal to you.
Having said that, however, there are a few basic things I try and do when shooting at the coast;
- Keeping some dynamism in the waves requires balance with the exposure. Too long and things can become too abstract. Too short and you loose the swooshery. Depending on the energy of the waves I typically will be looking at an exposure time of between 1.5 and 4 seconds.
- I try and include something bold in the frame, like a rock, pebbles or wood. This not only helps to create a visual anchor, but also can help with the swooshery, as the waves make their way around your chosen object.
- Filters are not always needed. If you are shooting in the moments before sunrise or after sunset you can sometimes get away with a longer exposure (2-3 seconds) without the need for an ND filter. That said, however, I typically will rely on a 4 stop ND filter from Formatt Hitech which can typically give me the exposure time I need irrespective of the time of the day.
The key thing is to experiment and play. The above 6 images all have the same settings in camera (Fuji XE2 + 10-204mm lens (24mm, f/13, 1.5 seconds)) and then the same very basic post processing applied (crop, exposure, whites and blacks, sharpen)
As you can see I've chosen a couple of anchor points in my frame, in the foreground, the middle and then on the horizon. Despite the exposure time being the same (1.5 seconds) you can see that each image takes on its own unique feeling, be that the shape of the waves in the bottom left of the frame, the amount of the foreground rock covered by water or indeed the presence (or lack of) of waves in the middle of the frame.
What I find when I take a selection of images from the same scene is that I can normally identify parts of each image that I like (or don't like). This in turn helps me to get closer to the final image that I want to make.
A few examples below ...
As I study the back of the viewfinder, after each shot, I look at the elements which are, to my eye, making the image stronger (or weaker). I then try and build on these in the subsequent frames. Of course this is mother nature we are talking about and it takes time. Pulling all of the various elements together into a single frame can be challenging. I guess it's a good thing then that I love to spend hours at the waters edge giving chase to the ultimate swoosh.
On that particular morning one major thing was missing in the frames above. Light, or rather the subtle pinks or dawn which I had hoped for. Thankfully about 30 minutes later the sun managed to break through the clouds for about 30 seconds and while I had changed my position slightly I still was taking on board the elements from the previous images. These helped to create the image below, which was my favourite from the morning.