Do your IFR in a twin. The incremental cost is lower than flying in a single, then having to build multi hours. Do as much as you can in a multi until you have 500 MEL.
Make up your mind to enjoy the journey.
Find out who the Santa Claus examiners are and ensure you take your checkrides from them, going so far as to do your training at a mom & pop, but do a "finish up" from the puppy mill. Or, go to a part 141 school with self-examining authority so as to not have any failed checkrides.
Don't extend yourself into a situation where you're trying to accomplish something before the old-timers in the industry think you should have it, especially if one of them is the examiner.
Don't start drinking. Avoid alcohol like the plague, same with smoking (why be ineligible for a part 121 carrier with an expensive habit (Alaska)?) Not started, you won't have to worry about timing, or how long 'til the next fix.
Learn to drink your coffee black.
Don't be the one that reports squawks, and don't be the one where the unreported squawks catches up with you, either during a ramp check or something majorly wrong happens inflight.
Get to a regional and out of probation as quick as you can. Then you can relax and go after fun type ratings, seaplane certificates, and other fun aviation events, if you have time and the money...
Learn to fall asleep anywhere, at any time, on command.
If you want to fly fighters, go for it.
Spend money on the online and CD ground schools. Knock all of the writtens out as soon as possible and get the ratings as soon as possible. If you even think you want to go for the airlines, it is best to get to the first regional job now, when the minimums are low, the various regs haven't kicked in yet, and a 250 hour wonder can be hired. Mortgage the house, sell the cat, put the children to work, whatever it takes to get in before the hours lock.
Miss a hiring boom, that's okay. There'll be another one in a few years.
Leave early, do the speed limit, get there early. Enjoy the few minutes break. No speeding tickets, no DUIs, no excitement.
If your friends are into prohibited stuff, find new friends.
If aviation is your passion, don't be afraid to enjoy the heck out of it. Every once in awhile, go up for a fun flight and enjoy it.
Be paranoid about your alarm clock.
Don't even think about working as a ramp rat, or in any occupation that requires lifting heavy stuff all day where you're not building flight time. Flip burgers instead.
If you're going to CFI, find a busy flight school with several twins, and get your time in there, get hired as a CFI, and get the CFII and MEI asap. Time is money in this case.
No matter what obstacles you face or setbacks that leave you with pieces, always keep getting back up for more. It ain't over 'til you're six feet under.
Your job as pilot is to say "no" when the situation calls for it, even if it is to the person that could fire you. If the flight is not safe, don't go.