The hose is usually the first to go to crap. All you can really do is blow through it a few times after each session and don't be surprised if some flavors tend to "ghost" (leave a taste in the hose from previous sessions. Some flavors are more prone to ghosting than others) which may mean it will alter the flavor unless you buy another hose.
Matt-641 is correct - to keep it from rusting make sure you keep it clean and dry as best you can. Invest in a couple of hookah cleaning brushes or a baby bottle brush set. You want one of those narrow cleaning brushes for the stem and hose port. The paint will peel off the vase, so just a forewarning there. Mine did the first time I cleaned it.
Clean it before you use it the first time. When you clean it use some baking soda and either pure lemon juice or white distilled vinegar mixed with warm water. Run it through the stem. Plop some baking soda down the hole and use the brush to scrub the stem and hose port. Then run clean water through it again. Blow through it to force the big droplets out and then find somewhere you can stand the stem upright on top of a hand towel to drain.
ETA: be sure and check out the how-to videos here on how to clean your hookah.
How to Clean Your Hookah: Beginner's Guide Part 1
How to Clean Your Hookah: Beginner's Guide Part 2