TL;DR: Work hard, save money, don't be an asshole.
Work hard, be good at what you do, and save every dime you can. Make sure you've got enough cash to maintain your life for 6 months. This can take time, it took me 3 years in my first tech job to reach this point, and didn't have much resembling a life during this time. It kinda sucked, but the investment paid off multiple times over.
Then interview aggressively. Interview for jobs you don't actually want, it makes good practice, and they're easy to reject. When you're researching the companies you interview for, look into why you'd want to work for them, not just into random trivia to demonstrate an interest in the firm (do this too of course). Remember that the interview is a two way street. You're interviewing them to make sure it's a good fit. Ask to look around the office, to chat to some of the people you'd be working with. Look at the nearest toilets to where you'll be working.
Do not be afraid to turn down jobs. You're not burning bridges. You can turn a job down and still join them later if you change your mind (if they're still hiring). If you've taken a job and decided it's not a good fit, do your best to impress as much as you can, as quickly as you can. Demonstrate your worth. They'll be disappointed when you leave, but you've left the door open for future opportunities with all of them. Having options is the closest you can get to free employment insurance. This builds your professional network, which leads to more and more opportunities in future.
Your salary is a function of your ability to negotiate. Interview for jobs you don't want to get offers. Salary negotiations are like prom dates. The more people that want to go to prom with you, the more people that'll want to go to prom with you. Desirability breeds desire. Having offers means you can negotiate higher, and get more of what you want. Their starting offer is their floor. They will only go up.
Go back to the beginning. Save every nickel and dime you make. You should increase your liquid cash to minimum 12 months living expenses (at the rate of expense of the life you want to lead, not at the rate of saving every nickel and dime). You should have additional savings, investments, property potentially if that's the right route for you.
Work hard, be good at what you do. If you are, and the people you're working with are too, mutual respect builds, and from that, friendship. If you're like me, 10 years in, you're no longer interviewing for jobs, you're chatting to friends about prospective opportunities where they're working. They've done similar to you, and they're only working in places with people they respect, so the effort involved on both sides of the hiring process goes down.
Invest in yourself, balance your life with your work (life-work balance, the ordering of that phrase is important), value your time. Don't work for anyone who doesn't. That doesn't mean you don't do crunches, just that they're exceptional rather than ordinary.