Tips for getting a meat loaf to come out just right?
You'll likely do better first trying a recipe, and see how it comes out and we can tell you how to adjust it for your preferences, but a few things to consider when making meatloaf:


Don't squish the meat or work it too much while you're mixing it; you'll end up with a rather dense meatloaf.  (unless of course you like that sort of thing).
Some people prefer on fattier grinds of meat for a 'juicier' meatloaf ... I personally go with 85/15 or fattier.
Mixing types of fat with different melting characteristics will also change the texture; for this reason, some recipes call for adding pork sausage, or a blend of ground pork, beef and veal.
Vessel is important -- some people will cook their meatloaf in a loaf pan; personally, I like a little crust on mine, but because of the grease that comes off during baking, I use a broiler pan.
Shape will affect the crust and cooking time -- a larger cross-section will need a longer cooking time, but the top may crust up too much; you can either tent with foil while cooking, coat with a glaze, top with bacon strips, etc.
Mixing the meat while chilled will keep the meatloaf less dense, but allowing it to warm up before cooking will allow it to cook more evenly.  (so the outside isn't overcooked while the middle's still cold; especially important if you're not going with a glaze or similar)
Almost any vegetables can be added as a filler, if you pre-cook them to soften and remove most of their moisture so they're not overly wet.  Onions, bell pepper, carrots, cellery, dark greens (spinach, chard, etc), summer squash (eg. zucchini, yellow squash) all work well.
To speed up cooking time, or if you're living alone and know you won't eat the whole thing, consider making smaller loaves.  You can even make it in a burger patty size &amp; shape for individual servings.