Since this thread has gone many ways, I will introduce yet another subject:
What tips have you learned that have really brought you closer to the "pro" sound?
The newest one for me is eq. It is making a huge difference in my latest stuff. I didnt use much on my first album because I really didnt know how to effectively. If I had a time machine, I could make it 100% better if I knew what I do now.

It really is an art and I am hardly an expert, but the difference is amazing. A lot of stuff I was actually doing backwards: stuff like bells and bell trees I would brighten, when actually I needed to do a high cut instead.

It's starting to add the "warmth" to my recordings.
How bout you?
The biggest one for me..
Hear with your ears, not your eyes, or your brain. - not getting caught up in what's correct technically, because nothing is actually...correct. It either sounds great or it doesn't. If it sounds great leave it, if it sucks, fix it, regardless of what an electronic meter is telling you.
And..
At some point... just stop, or it will suck. - With computer based recording it's so easy to have the tendency to want to tweak it forever just because you can. Sometimes, you can lose the original charm if there is too much tweaking. Sometimes, to force myself to do that, I'll actually export sessions as multiple wave files, and make a new session, burn the old session to a dvd, so that it makes it very inconvenient to tweak it.. then I'm stuck with what I have.. and I find, it often makes the result much better than tweaking it forever and ever, without anything stopping you from changing the entire thing at any moment.
And..
Distortion is your friend - (hey, that's even what people enjoy about the sound of nice analog gear, the pleasant distortions it introduces) Sometimes throwing on small bits of distortion can get you closer that some "vintage tube wigawahootzit.vst" (I must say, PSP Vintage Warmer is quite nice however)
And the actual biggest one (I lied):
Musicality. - So this means, the arrangement, the particular instruments chosen for the song, the ability to use someone's playing abilities and style x 10, a comfortable, relaxed, working environment for anyone who is involved. Willingness to experiment, even if it seems insane (that's how techniques are born), willingness to listen, but also to filter suggestions.
No matter how good of gear you have, or even musicians...the parts should partially mix themselves before you even touch a fader or effect. How to make a mix full? Just ensure that it's written to sound full. If the players are playing something that doesn't help in that dept. it will never sound quite right if you try to make it sound full... or whatever.
So yeah, you look at pretty much anyone who churns out really good stuff and there is always someone involved, or the person themselves who are not afraid to talk to the band about the arrangements. I won't bat an eyelash if I'm working with a band, even if I'm not technically producing it, before going up to them and saying, okay you want it to sound this way? Let's talk about the arrangement and how we can achieve it that way, as that will sound the most "pro".
oh.. but yeah...all the other normal stuff helped too.
