If what you mean by "mastering" is slapping a brick wall limiter on the master bus, then by all means, mix to -0.1 and watch Bob Katz cringe. If you are delivering songs for professional mastering, you shouldn't, in the mix phase, push the volume so high at all. The mastering engineer needs some headroom to work with. Otherwise, the first thing he'll do is gain down the total volume of your mix, thereby reducing the dynamic range you had available. 
 
As for normalize, normalizing isn't compression. Normalizing simply means bringing the highest peak of your music to a set value, usually 0dB or -0.1dB. It doesn't change your dynamic range other than raising your noise floor. If you ever got a "sausage" type file you were first compressing. Without normalizing you would still have gotten that sausage, just a thinner one. 

"I do use plugins almost on every track. I like what you wrote: Conclusion #3: Use mixing to get the balance right. Use mastering to get the levels right. Still I think when you mix, you may as well have it as close to where you like it to be as possible."

I believe your last sentence is where you are missing the point

When you MIX instead of aiming for -0.1 aim for -6 and turn up your monitoring so that it still sounds as loud as you want it when mixing

THEN load up OZONE on your master bus and use the tools to get your mix up to -0.3 by using the final limiter within Ozone

Everyone else has explained the reasons WHY this approach is considered better and trying to argue against this advice is stopping you from achieving what you want - and what you asked for help with

To achieve what you want (louder mixes to compete with commercial recordings) I would suggest just trying to work this way on a mix you have already done

Save a "mix scene", remove Ozone and then mix so the meter is bounding around -6db(ish) on the master

This will mean reducing the fader/gain levels on your tracks so start your mix from scratch with this new target in mind

As CRAIG says, when mixing you are worried about the balance and clarity of the elements

When you have the mix sorted and it is bouncing around -6 on the master use Ozone to bring the level up

If you are just throwing random Ozone presets on I would suggest watching a few videos on your version of Ozone so that you can tailor the preset to your particular needs as it will sound MUCH better

Hi,
Iv'e had an experience a couple of times where I think I'm sending something to soundcloud,that SONAR shows I'm below -0.1,but OZONE 7 will indicate it's clipping by being over,like +0.1 or even +0.3,I'm obviously making my tracks too loud anyway,so I'm in the process of making sure everyone[Platinums meters plus ANY plugins],are AT Least -0.3 or less.
Bob Sattler

I disagree with the assessment that you leave the loudness until the very last step. If you are serious about getting a loud track then you'll probably be putting clippers or limiters on percussion tracks (at the least) early on. This is not because there's a problem with tracks peaking low before you sum them - as that can be made up for with gain later in the chain - but because you want to have an idea of how attempts to get loudness are going to affect things down the line. The mastering engineer doesn't have as many options as you do (eg. re-tracking, automation, transient shaper) so you need to make sure you're not giving them an impossible task.

Kylotan makes some good points.
 
On most of my recent mixes, I've mixed right INTO my mastering chain so I immediately know how the chain is affecting the overall quality of the mix and also a very accurate idea of the final loudness.
 
You do need to calibrate your monitors if you go down this route - mine are calibrated to 78dB.
 
85 is too loud for my small room.

I agree that once you understand what is going on you can "mix into" a mastering chain
 
The lines between "mixing and mastering" are definitely getting blurred now that PCs can easily handle a whole mix project with loads of plugins AND a complex mastering chain
 
 

vladasyn
I mix to -0.1, then limit peaks by master limiter and bring it slightly higher.

I suggest you take several steps back and reconsider your 'normal' ways of mixing and mastering.  Read some good books, listen to the professionals here, go back to school.  Forget for a moment how you currently do things and open your mind to what others may have to say.  There is logic to the tried and true.
 

Boydie
I agree that once you understand what is going on you can "mix into" a mastering chain

But is it a good idea to do so ?  Kylotan mentions mixing while keeping mastering in mind.  That's not the same thing as mixing and mastering at the same time.  I understand that mixing and mastering have different goals and require  different mindsets (and tools) to acheive them.
 
Say you're building a piece of furniture.  It doesn't make sense to final-sand some pieces while rough cutting others since you'll undoubtedly have to resand them after they've been knocked around for days waiting for final assembly.  It's better to do things in stages, in which you set things up and lay out the tools needed for each stage, and methodically work your way through the stages to the final product.  If you try to jump stages for different parts you invariably end up having to redo the later stages for certain parts, and maybe even risk starting over if you missed something important.  You end up jumping around chaotically trying to do everything at once instead of steadily converging towards the final product.
 

The only thing I "mix into" is a master bus compressor.

You can mix into 2-bus processing, for sure. Lots of mixers swear by it. But that is in no sense "mastering".