The traditional advice is “ask and you shall receive.” That’s not terrible advice, as far as it goes – people don’t magically know what you need or want, so step 1 in getting anything is being able to communicate.
There are ways to ask more effectively, though!
When I was just a kid, I picked up on a marvelous pattern with my parents. If I said, “Dad, can I have twenty dollars to buy something,” I’d either get a flat “no” or I’d get a long list of arduous chores to do in exchange for the funds. Not only was this usually a low valuation of my time comparatively, but I was never able to refuse – for one, saying “Nah, not worth it” would make me look lazy in my father’s eyes (an absolutely cardinal sin), but for two, even if I wanted to refuse it was too late – now that my father had itemized the list of chores, he’d make me do them whether I wanted the money or not.
However, if I instead came to him and said “Hey Dad, if I do all the dishes and pots before I go out, can I have twenty dollars,” I’d get it 99% of the time. Washing a day’s worth of dishes and pots wasn’t worth anywhere near twenty bucks, as it would take me about 15 minutes and was low-effort, but coming to the table with an offer first would both show the right attitude (always a winner) and create a tangible value trade, albeit a skewed one. Occasionally he’d throw in something extra like “take out the trash too and it’s a deal,” but the strategy was definitely a great one.
This is true in everything you do. Don’t say, “Hey, can you give me a ride to the airport on Thursday?” Try: “Hey, if I buy you breakfast, can you give me a ride to the airport?” A good friend might not even cash in the breakfast, but showing that you value their time is a great way to endear someone to you.
Don’t just ask for a raise. Say what new task you’d like to take on in exchange. Don’t just ask for an interview. Say you’d like to create a project for someone and then ask for time to review it together.
Not only does this strategy work from a psychology perspective, it’s also fantastic because it lets you set the starting terms of the negotiation.
If you just ask, you might get a yes. But you are also likely to get a no, or a conditional yes with the conditions set by the other person. And you’re in a bad spot to negotiate, because you’re the one who was asking for the favor in the first place.
Get help by giving it, and your world will drastically improve.