Which island type do you like the most?

[Aanchir]

I like both slopes and curved slopes a lot. The multicolored water approach from the Friends Beach Amusement Park is lovely too, but I think for many  Pirates builds it's unnecessarily parts-intensive (whereas in the Beach Amusement Park it served a very practical purpose, raising the "ground level" a bit higher so that there's room underneath to conceal the interconnected Technic mechanisms).

Several of these techniques can also be combined in interesting ways if you're clever about it (for example, using rocks along the coastline to separate the different coast styles so the transition between them is less abrupt).

And obviously, depending on the type of build you intend to use these coastline techniques for, you might need to adapt quite a bit. Like, if you want to suggest a grassy tropical island instead of a barren sandbar/desert island, you're gonna have to include a layer of green plates or tiles no matter what type of technique you use for the sandy beach portion of the build. Some of these approaches allow for a narrower beach than others, while others might be more effective at locking together the plates underneath if you choose to give the surrounding water an irregular footprint using a mix of standard plates and curve/wedge plates (as official sets often do).

[Captain Becker]

I like em all! Classical is always nostalgic and easy solution, detailed multilayered adds a bit of realism, and the tan cruved slopes and shapes are fun to explore and to make little sand dune islands.

Captain Charles J. Becker