Hi Dan!
Welcome aboard!
About the weathering there are lot's of technics that you can use, depending on scale and type of vessel. 
The most important thing is research. So search the web (easy and cheap) for images of the vessel you are building and try to find where the weathering occur and what type of weathering you're going to apply - don't make mistakes like rust patches on a wooden hull 

 so this part is very important!
When you discover waht kind of weathering you are going to do and where to do it, we can start talking about the so call technics:
 - hues of the base colour: you can apply some hues of the base colour, mixing little dots of white, or light gray (to lighten) or dark gray, black or sometimes dark blue (to darken). This can be used in small patches or areas where the sun/salt have faded the original colour, like the horizontal areas of superstructures, or parts of the hull. These hues should not be very different of the base colour to avoid the "measles" effect 

 very subtle and not overdue may do the trick!
 - Rust: can be made using enamels, artists oils or even pigments / chalk pastels. (see 
https://armorama.kitmaker.net/review/815) 
I would advice you to try it first on an old model or if you don't have it, a cheap one - you don't want to "burn" a lot of $!
 - Wood weathering (decks):  Again artists oils and turpentine can do the trick. Yellows, Burnd Sienna, Raw Humber and Green will give the wood that worn look!
These are only some tips, from my preferred technics, but there are others. Read some reviews, online or mags, try a little, so 
that you can find the one that you feel more confortable with, with the expected results! This is the most important bit!!
Don't be a stranger - show us your work and your progress!
If you need any more help, have questions or just say hello 

 we are here!!
Skipper