I assume you're starting with powdered wheat gluten and not white flour (the later is slightly more involved). Here is how I did mine recently:

• Mix ~140g of wheat gluten with ~40g of white flour in a bowl.
• Add about ~240ml of a broth (vegetable broth / vegan chicken broth).
• Make a dough. It should be cohesive and not too sticky; if it's too sticky, add gluten. If it seems too powdery / too dry, add some more broth.
• Cut the dough into 4/5 parts. This is very important - they'll grow up during cooking and your smaller doughs will cook faster.
• Now for the cooking broth. In a bowl, mix 37cl red wine, ~50cl of a broth similar to the one above (like a vegetable broth), 3 large spoons of tomato paste, 4 large spoons vegan worcestershire sauce (or a similar tasting sauce) - not a large loss if you don't add the last one, though it makes the favor a bit more complex IMO. Add spices as you feel (I like to add some cumin, for example - not too much).
• Cut two onions and crush 3 garlic gloves.
• Brown the onions as you would normally into the bottom of a large pot with some oil; add the garlic when it starts to look good, brown the garlic a bit.
• Now put your cooking broth into that pot on top of it. Add your seitan in it. Now add water until the seitan is covered.
• Cook it up. You'll want to maintain a simmer (right before boiling), for about 50 minutes.
• Remove the seitan, put into tupperware; then add cooking broth in tupperware so that the seitan will be imerged while being stored in the fridge. It's ready at this point. When needed, remove a blob of seitan from the tupperware, dry it up roughly with a paper towel, and cut it up.

Now for the great part, reducing the leftover cooking broth (the one that's still in the pan and didn't make it to the tupperware) to get a sauce:

• Prepare one or two (depends on how much broth you still have) large spoons of either white flour or corn starch, and mix with some cold water into a bowl.
• Now put the heat back on on your pan; this time you can boil, though not too strong. The aim is to reduce the quantity of water here, usually takes me around 10/15 minutes. The best way to judge is to taste it regularly: when it starts to taste less like flavored water and more like a much too liquid sauce by its own / starts to have more taste, you're ready to add the thickening mix.
• Add your flour/corn starch thickening mix. Cook for a few minutes until the consistency of the sauce seems right.

The sauce is delicious, and the seitan the above produces is pretty good for me - firm texture and so on. Add strips of your seitan to rice or noodles, cover with sauce, sprinkle some sesame seeds on top, and you already have a nice meal here. I like to add steamed carrot pieces to that meal, too.

Of course you can go further with the seitan then; I love this recipe for example: Vegan Mongolian Beef.