a full custom is the best way to go. you can but starter kits. they come with everything you need. I would go with any kit the has a D5 pump. XSPC has some great kits. I would suggest you get aftermarket tubing. 1/2 in x 3/4 in would be best.

when it come to fittings that is down to your preference. barb fittings are the best for new comers because they seal better. but compression fittings are quicker.

for the liquid the best to use is distilled water with a silver coil and some dead water drops. don't use any dyes or any of the other crap out there. they can clog the system and dye the tubing. if you want UV then get UV tubing.

any other question just pm me and i get back to you.