First of all go study mixing 1st, then mastering. There are two exceptions to studying mastering 1st before mixing:
1st If you really need to master a set of songs now, as in your friend or maybe you made an EP or album and you really need the mastering done, by all means go do the best you can and self-study mastering.
2nd Unless you're going to specifically enroll on a mastering course and want to eventually work as a mastering engineer, stick to mixing 1st.
NOW If what you mean is the "workflow" on mixing, as in the order of what you should do, that can be, for the most part subjective.
Sometimes, For me personally it slightly differs per song/track as I do my own synthesis and sound design as well.
There is a rule of thumb, which I personally almost always, but not ultimately adhere to. This is going to VERY VAGUE and again there are times I do change the order of this in a course of a mix. This workflow is assuming that you've got all the sounds you like in place and you're done with the production stage of your track (creative use of effects to achieve the sounds you want/sound design).
Generally I do things in this order:
1. GAIN STAGING - nothing else to use but the faders in you DAW. Set the levels of your tracks to your liking, balance is what you should be after here. (while avoiding any clipping)
2. BUSSING/GROUPING - Group tracks into buses like drums, basses, High freq sounds etc. This is not necessary but it makes life a lot easier and If you've already done this in the production phase before gain staging, that's fine.
3. HP/LP FILTERING - this is a personal technique of mine. I prefer to place a dedicated HP/LP filter to individual tracks and use it accordingly before any other effects, trust me it's better this way.
4. COMPRESSION - Determine which tracks actually NEED Compression. Not all tracks need compression. The tracks that already sound consistently [dynamically] good to you, no longer need compression and again by this stage, you should be done with using compression creatively or for sound design.
5. EQ - like with compression not all tracks actually need it but with EQ 90% of the time they do. Your goal here is to determine the important characteristics of each track and making space for them in the mix. Like for example, doing a high shelf cut on the piano track to make space for the hi-hats and conversely cutting 500-600hz on the hi-hats to make a little bit of space for the piano. Then boost the main characteristics of each track IF NEEDED. I suggest doing cuts 1st before any boosts.
6. DO YOU PANNING - this is when you decide with elements of the song will be panned left or right.
7. OTHERS - This part is usually where I determine what tracks need gating, reverb, Multiband compression, Dynamic EQ, saturation, some more stereo manipulation, checking the Sum and difference (MID/SIDE), noticeable phase issues, etc.. This is mostly the corrective part of mixing rather than "sweetening". This is more advanced stuff that I can't go any deeper because it will make this reply more irritatingly longer than it already is
8. 0 DB - This is a personal thing. I know I said in gain staging that you should avoid clipping but some times after all the mixing, you can go well under 0 DB. So what I like to do is loop the song at its loudest part and just adjust the volume fader where it hits exactly 0 DB. This can get tricky and you won't always get it 100% right. If this just confuses you just make sure on the master fader NEVER goes beyond 0 DB. Almost always its better to be under 0 DB in mixing, but not to the point that it's too quiet.
AGAIN this is all fluid and not set in stone. Also I don't want to talk about the order of the plugins (eq before comp & vice verse) as this is really different for every track on every song. Things like these are easily googled.
1 TIP & A TRICK:
Let you ears rest at least every 30 min. Let your ears decompress, take adequate breaks.
Use commercial professionally mixed & mastered track as reference as much as you can. (but not to the point that you use it every step of the way or if it slows you down.)
IMPORTANT NOTE:
I mentioned my workflow because I assume that you already know, in general, how the tools work and how to use them (EQ, compression etc.). If that is so then I just have my workflow as an example in the hopes that you can build your own workflow as well.
How well you do each stage in mixing really depends on your knowledge on how and when to you use your tools, how trained your ears are, how familiar you are with you listening equipment, and ultimately practice and experience. Again I'm sorry if this is somewhat vague advice.
If you are still confused with how and when to use the tools, the best advice I can give you is KEEP GOOGLING AND REVIEWING.
Google, read, study and absorb everything you can. I won't give you details as there are a ton of materials out on the web.
JUST BE AS INQUISITIVE AS YOU CAN. If there's a word or phrase in what you're reading that you don't understand or catches your attention, GOOGLE IT! No matter how weird your questions are GOOGLE IT! Personally I spent my High School and early college days with this general idea as my pastime and procrastination, just googling stuff.
AS for the sources here are the best and most organized ones:
therecordingrevolution.com also look at Youtube check out the playlists on that channel.
Joe Gilder on Youtube again just look at the playlist on that channel
SoundonSound.com
Musicradar.com
If you find that you lack some tools, check out the free stuff mentioned on Bedroomproducers.com
If it's added knowledge you're after, just keep searching stuff you don't know yet.
Honestly if the linked soundcloud track (To The Other Side) was mixed entirely by you and you could actually say that you genuinely knew what you we're doing the entire time, as opposed to just "sometimes-fiddling-around-til-it-sounds-good" you're actually 70-80% there skill wise. Now unless you're passion is really the art of mixing, then by all means keep self-studying/searching as hard as youcan, BUT if you're partly a musician, composer, producer, songwriter etc., I suggest you slow down on searching/self-studying. You're better off focusing on making more music than loosing more of your time studying the technical things like mixing and mastering.
IF you are a musician, composer etc., then what I do encourage is to study is music theory, arrangement, forms & Analysis, songwriting and the like.
I know this has been said at least a thousand times already but it bears repeating: I'd rather listen to a good/great song that was mixed "okay" than a crappy song that was exceptionally mixed and mastered.
If your song's main asset is the way it's mixed and mastered, you might get a shot on having a job as a mixing/mastering engineer.
If your song's main asset it the song itself, you might get a shot on getting a record deal.
Assuming that you're in a home Studio type setup, in my opinion you're pretty much good to go mixing wise (unless you're aiming for the big leagues as a mixing engineer).
PS I have to much free time right now.