Have a go at this tutorial. Make the sea yourself, no cheating.
Here is my attempt.

wow!! very good il have a go now...

heres my go


only joking i'll have a go later, off to bed... only just got in

I'm having trouble with the sky part....

Mode: Linear dodge, Opacity 30%, Flow: 50%

How do you do that? I tried changing the mode and opacity on the layer options, is this right?

and can't find where to change the flow..... im sure i've done it before though

I gave up with the sky, I just used a lightning brush and a cloud brush and did a reflection....



Reflection is not perfect but oh well!

Neither is the sky though!!

Managed to do it (silly me!)

Here is what I got:

Well done. lol

I have a really good tutorial somewhere, it's dead long but it's really well written. I will look for it now. I have found that a lot of tutorials are really badly written and I try about 3 times then have to give up.