I use stew beef (chuck) because it's very flavorful and gets tender as it sits a-stewin'! This recipe is for use with a slow cooker. Variation for stove-top or oven follows. Like Pete, I wing it each time, but there are certain constants.
Keep in mind that you could make this very easy and just take all these ingredients and toss them in the slow cooker and thicken when done. However, the browning and deglazing does add a good layer of flavor to the finished stew.
You asked about flour vs. cornstarch. For anything needing a gravy, per se, I use flour. If it's a liquid in a pie, fruit crumble, or something else that should be more translucent, I use cornstarch. I guess that with some exceptions, it's flour for savory and cornstarch for sweet.
I brown a thick chuck steak or thin roast on the grill to carmelize the outside. It's not required, but I like to think it adds to the flavor. If you don't grill it you can use it raw or brown it in the pan you use for the onions before you do the onions.
While that's going, cut two medium onions into a large dice and brown with olive oil in a pan, stovetop. If desired, trim and quarter about 8oz baby bella mushrooms and pop them in with the onions. Cook on medium-high until the onions are medium brown. Deglaze with 1c red wine (always use a wine you like to drink, or broth if you don't like to use wine) then add it all to the slow cooker. A little more wine won't hurt!
Trim the fat from the beef, grilled or not, and cut it into 1/2" - 3/4" cubes. Throw it in the cooker.
Cut about 3/4# carrots into medium chunks, about the same size as the beef. Same with about 2 large potatoes. Cut 2 large ribs of celery into half that size. Use more or less of each veggie depending on what you like. Throw it all in.
For seasoning, I use the leaves from a few sprigs of thyme, chop about 1T rosemary leaves, 4-5 cloves of crushed /chopped garlic, a sprinkle of black pepper, a dash of nutmeg, a couple dashes of worcestershire, and a few bay leaves. Remove the bay leaves before thickening the broth later.
At this point, add in whatever other raw veggies you like in your stew but don't fill the slow cooker more than about 2/3. If you want to add some frozen peas or something, add about 1C near the end just to heat them through.
Add low-sodium broth (beef, veg, etc) to bring the level to about 3/4 full. Slow cook on low all day or high 3-4 hours.
To thicken, employ a beurre blanc or flour slurry. For beurre blanc, mash equal parts butter and flour together into a paste and stir it into the bubbling liquid. For a slurry, mix flour and broth (or water) into a thick liquid and whisk it into the broth. Add slowly and allow it to come to a bubble before adding more as it thickens as it heats. I usually use the slurry.
If you do this stovetop, use a heavy-bottomed pot. Brown the cut meat in a little oil and reserve. Brown the onion (and mushrooms if used), then add seasonings and stir for a minute before deglazing and adding everything else but the thickener to the pot. Simmer gently, covered, for 2 hours. Thicken when done.
For the oven, use an oven safe vessel and follow as for stovetop, but put in the oven, covered, for about 4 hours at 300.
I don't add salt for dietary reasons as there's enough in the reduced sodium broth for me. If you want to add some, go for it. Same with any other seasonings you might like. Stew is a great "use it up" meal!
Good luck,
Chuck