Since we still don't have a thread in here for general music theory discussion I thought I'd start one.
Personally I'm pretty new to it and have no formal education in it so far. Earlier this year I started looking a little more for basic theory stuff online and started learning a few more fundamental things. Prior to that my theory knowledge pretty much consisted of knowing the intervals of a few different types of scales, being able to form basic major and minor triads and, in the past year and a half to two years, starting to become comfortable with various inversions of the basic 3-note triads and picking out melodies using mainly those notes.
Going forward again to early this year, the first thing I found to help me progress from the above was
Introduction to Music Theory, which I would recommend to anyone who feels like their understanding of the very fundamentals of music theory is lacking.
After getting acquainted with the material above, I found something on Youtube a month ago (to the day, I think) that felt like it was exactly what I'd been missing for years. I don't even think the results of joining cardrunners as a 25nl player back in 2007 can rival the impact
these counterpoint lessons had on my music.
It's a 15 part series made by an enthusiastic and seemingly quite knowledgeable Italian guy when he couldn't find any information on the subject on youtube. The first 14 parts are all under 10 minutes and as long as you're somewhat familiar with the introductory content in my first link you should be able to get most of it.
Unfortunately one or a few of the later videos have no audio, making them a lot less useful for a notation/theory noob like me who relies on the explanations and actual music a lot. Watching the ones with audio is still well worth it though and I'd recommend the series to pretty much anyone who has some sort of interest in writing melodies and isn't already quite familiar with counterpoint. He also has a series on harmony that I have yet to really get into because I needed some time to digest the counterpoint ones first.
Anyway, this is turning into way too long of an OP for just a couple of links. Hopefully the links will be helpful to some of you and those of you already familiar with the content will be willing to help the more noobish of us when we have questions that we can't find the answers to amongst ourselves.