Audio Lessons Learned - post your best advice for the newer members!

Audition gear at home, if possible. 

DO NOT start chasing the dragon unless you are paying a mortgage.
Have your life-priorities straight: Food, shelter, clothing and a secure job.
Don't throw piles of cash at audio equipment until you are relatively secure.
If you are paying for the basics, you'll know what you can afford for equipment.
Also, no matter how much you spend on your system, all it will do is play music. Be sure to ask yourself "how much do I like music?". It's easy to get caught up in the race thinking an expensive system will COMPEL you to listen more often. 

DIY. IF Carter can make his own furniture, then why not learn from his inspiration?

Ignore the advice of audiophiles who took almost 50 years to make the right decisions.

Excellent thread and lots of great advice so far.

I'm pretty new to this , I've had music systems for years but to actually get into getting great sound and being an audiophile it's only been the last 2 to 3 years, but forums like this (If you can save through the nay sayers and those with something to promote) can serve you very well. 

Do your research, swapping out good components will burn your cash. It's not just about components the details really matter and you should budget for that if you want a great sounding system.

What are the details? these 3 top 2  most important for most people but it will depend on your system and home.

In room response of your system, so speaker set up including the right speakers for your room, room treatments or effective use of home furnishings and Digital sound processing. DSP works for me , I don't have a dedicated listening room so high WAF and room utility.

Power management , including ground. This is a very localised issue to you but is critical to some homes. If you are in your home for the long term well worth the effort of infrastructure investment. 

Resonance and vibration control,  this can make a surprising difference once you have the other stuff sorted so that your system can resolve these effects. I think decoupling is superior method and this applies to solid state digital as well as valves and turntables. There are lots of well engineered pieces at very high prices but some good stuff too on the cheaper side and lots of scope to DIY cheaper options.

Don't put too much faith in measurements,   they can be useful but are only a guide and many things we can hear are not able to be measured. Digital streaming playback is  not just a case of sending 1s and zeros (although many many network and computer guys will call you insane for stating such).

Compressed music formats such as MP3, YouTube and  spotify can sound fantastic if you get your digital system right (hi rez is then the cherry on the top). 

If you can get a subwoofer or subwoofers, getting that last octave or 2 really makes a massive difference but integration is critical.