The best advice I can give you about making soup is to try making your own stock.
I know you don't have time; I know that there are "good" broths and stocks available at "Whole Paycheck", I know people like Ina and Rachel tell you that store-bought stock is okay.
But I'm telling you from my experience of making soups for many, many years: the soup always tastes better if I start with HOMEMADE STOCK!
And besides that, here are some other things I've discovered:
It's not difficult.
It doesn't take that much time and effort.
It's inexpensive, since all of my stocks are made from parts of meat, veggies, and fish otherwise thrown away.
Let's start with a simple veggie stock.
Any time I cut up veggies for a mirepoix (onion, celery, carrot) any discarded parts, including the bottoms, tops, and skin of the onions and bottoms and tops of celery and carrots, get stuffed into a ziploc bag and thrown in the freezer. Also, anytime I clean out the veggie drawer in my frig, old dried up baby carrots that I wouldn't serve and limp celery get thrown into the freezer. I also will save a stray potato gone soft but not rotten or other root vegetable (except maybe sweet potato since that has such a distinct flavor). Old tomatoes and tops and bottoms get thrown into a separate bag. They're good for starting a vegetable broth that will be made into a tomato based soup, but you don't usually want that taste in a straight up vegetable stock.
Then when I have 2 or 3 bags of remnants and I'm in the kitchen doing other things, whether making dinner or baking, I'll throw the contents of those bags into a pot of water and boil the shit out of 'em. Like I mean really boil the shit out of them. That doesn't mean a rolling boil, it just means simmering for a really long time. Until they are mush. It could take 2 hours, but that's not time you need to tend it. I've put pots of stock on a low simmer and gone shopping. I usually partially cover the pot, letting steam escape so I don't have a boil over situation. Sometimes foam will form. Don't worry about this. It will be fine. This ain't rocket science.
When the veggies are almost unrecognizable cuz they're so mushy, you'll pour the stock through a screened colander. You really need a screened colander for this because there will be small bits of veggies you want to strain out. What you will be left with is an amber-colored stock imbued with the flavors of whatever veggies you put in it.
OPTIONS: I'll throw some fresh herbs in with the stock, such as fresh thyme sprigs, oregano, or even sage, whatever I might have lying around. Whole leaves are good because they'll be big enough to get stuck in the colander when you strain it. I do not salt my stock. I leave that task for whenever I use the stock. So when you taste this stock without salt, you might not think much of it, but believe me, the flavor is there! You have wrenched the flavor from those veggies by boiling them within an inch of their lives.
From there it can go straight into the freezer in sealed containers or you can make this fabulous albeit very simple butternut squash soup.
For this soup, I had a container of veggie stock in the freezer I needed to use up.
Roasted Squash Soup
2 small - medium butternut squashes
1 large onion, diced
1 chipotle pepper in adobo sauce, diced finely
1 roasted red pepper, diced
6 cups homemade veggie stock
juice of 1 orange
1/2 to 1 cup half-n-half
1/4 teaspoon ground coriander
1/4 teaspoon ground cumin
1/2 teaspoon hot curry powder
a few leaves of fresh sage
salt and pepper
GARNISH: fresh jalapenos and cilantro
Preheat oven to 400 degrees Fahrenheit.
Split squashes and de-seed. Baste generously with olive oil and salt and pepper liberally. Roast them
cut side up for approximately 40-50 minutes. They do not have to be mushy done. If they are fork tender but the flesh is still a little resistant, that will be fine. You just want to roast them until they get that yummy roasty flavor and they are easy to scoop out of the skin. When they're done, let them cool a few minutes so they're easy to handle.
Saute onion in olive oil in a large heavy-bottom soup pot for 3 minutes. Throw in chipotle pepper and seasonings and saute another 2 minutes.
Pour in stock and bring to a simmer. Scoop out each squash half and add to the pot. Add orange juice.
Let simmer another 10 minutes, turn it down to lot heat and use a hand blender to smooth out the soup. Once the soup is smooth, slowly add the half-n-half stirring to blend.
Cilantro makes a nice garnish. If your folks like heat, garnish with fresh jalapenos.
More stock advice to come!