So I have a map and am making an island type area, and want a beach with the sea against the sand. I have tried making a terrain patch and lowering it with the gradient of a beach and adding water so the bottom of the gradient is below the water, but it doesn't work. either:
the whole terrain patch is invisible and you just see flat water
the water forms a flat straight line against the terrain patch
triangles of the terrain are invisible, ruining the whole look.

im unsure how to fix any of this, and should my terrain patch be a big brush or small one? and how many "triangles"?
when I make big ones with lots of triangles (just for adding grassy patches to the sand) lots of triangles are invisible and it ruins my texture, also the terrain patch next to my sand textured brush with the same texture shows a really tiny, compressed version of the texture. the regular brush looks perfect but the terrain is all compressed as if the texture is much smaller but repeats.

It really is hard to explain what is happening, but if someone could help or point me in the direction of a guide to using and texturing terrain patches it would be hugely appreciated

Select all the patches together and press 'S' and then choose whichever setting looks best, probably CAP, Natural or LMAP. Also make sure you lightmap the textures using shift+L.

Ok that fixed my textures and the water aligning correctly, thanks

But half of the Triangles on my brush/terrain still appear invisible in game?

Ok that fixed my textures and the water aligning correctly, thanks

But half of the Triangles on my brush/terrain still appear invisible in game?

Did you shift+L, then 'S' lightmap/natural them (you should have the white/grey squares)? This is not the same as 'S' then lightmap/natural without pressing shift+L.

sorted it! Thanks man!