I have surpassed a lot of my peers who have made significantly more than me in net worth & possibly net happiness. Here's how:

1) Maximize your employee 401K benefits - This has been stated before but 401k matching is tax sheltered and more importantly, is free money from your employeer

2) Treat your credit card like a debit card - Never carry a balance, never use it to buy things you don't have savings to buy.

3) Carry cash assets in high yield savings accounts - While interest rates currently, suck, there is no reason to let your money sit in a non-interest bearing account.

4) Avoid paying tax on income as much as possible - There are a lot of financial instruments (401K, IRA) that allow you to defer tax. If you are in a state with significant tax rates (i.e. California) deferring tax can hugely valuable.

5) Learn how to financially model - This is probably my most valuable tip. You should understand the implications of every significant expenditure you make. Since I love modeling, I go a bit overboard on this but it really makes your decisions a lot more clearer. Some typical decisions that you should be able to model with a DCF: competing job offers, buying vs. renting, going to grad school, etc.

6) Financially model & think heavily before going to graduate school. As you hit the mid to late 20s, you may feel a lot of pressure to go grad school due to changing careers, getting pedigree, peer pressure, etc. Higher education in the US is extremely expensive; make sure you model the costs (including the lost opportunity cost of salary) before cutting a check. I've had a lot of colleagues waste money on MBAs that were largely un-necessary. There are also a lot of ways to switch careers without another degree (I did it myself 3 times without any new degree).

7) If you are open to working outside of the US, consider working for a few years in countries like Dubai where you can legally reduce your tax payments. A reduction in your taxes can easily double or triple your take home salary (even if your salary stays the same or even reduces). This benefit erodes as your salary increases so consider this in early stages of your career (it also becomes harder to move internationally as you grow older).

8)Negotiate every salary offer, ideally with competing offers, even if the offer is your dream job. Most people stop looking for jobs when they are close to the offer. What do I do? I accelerate my interview process and reach out to competitors to see if I can get competing offers before I have to decide on the offer. No good company will fault you for negotiating your offer and negotiation almost always improves your offer significantly.

9) When comparing & contrasting offers in different cities consider your "savings income": i.e. pay - taxes - living expenses. Some people instead rely on cost of living which results in incorrect decisions (a 50% increase in cost of living doesn't mean you need 50% higher in salary to net the same money).

10) Choose credit cards that give you the highest cashback (usually). This isn't always the right choice (i.e. if you fly a lot mile cards may be better) but in most cases 2% cashback card will beat out any card and cash is conveniently liquid (unlike miles). Also don't open more than a few cards as that will just open you to risk, abuse, and a lower credit score. Do NOT open a credit card just to get a free t-shirt or $40 off a purchase. My rule of thumb is that a credit card should return at least $300 annually (not just the first year).

11) Try to allocate expenditure on your "happiness ROI". I am extremely frugal on things that do not improve my happiness for the long term and relatively extravagant on things that do.

Things worth splurging money on [for me]: Experiences & travel, reducing commute time, fitness activities, books, a comfortable bed
Things probably not worth splurging on [for me]: Fancy & shiny new car, a bigger apartment/house, expensive new furniture, expensive non-work clothes

As you get older you will feel a lot of peer pressure to buy the things your peers are buying - don't cave in and focus your discretionary spend on things that make you happy.

12) Keep your cost of living relatively stable when your income spikes. You are likely to experience a income spike sometime in your career. Resist the urge to scale up your spending immediately - unless you were unhappy before (and purchases make you happy), what's the point? You will thank yourself when you experience the other common salary spike across most careers: lay-offs.

13) Build 6 months of runaway as soon as possible. Ideally this should happen within few years of graduating (assuming no loans). Extend the runaway as your career progresses and esp. if you want to be become an entrepreneur.

14) Depreciation is your friend - consider buying used when it makes sense. Many items lose significant value within a few months even though they have the relatively same value to you. Purchasing used makes a lot of sense in many purchase decisions (books, cars, furniture) but also makes no sense in other decisions (mattresses, bike helmets, swimsuits, car seats).

15) Advanced tip - Make sure you read the Intelligent Investor. Chances are you've been brainwashed with way too much EMH theory in undergrad which has convinced you that you can't pick undervalued stocks because the market prices everything perfectly. This book will teach you the flip side of the coin - the side that guys like Buffet made billions with. Even if you don't want to invest in stocks or mutual funds, it will give you the right philosophy for financial decisions.