I use a kick synthesizer for the body and tail of my kick which gives me control over the shape and tone, so all I usually do is high pass the sample I'm using for my topkick so there's no interference with in the bass frequencies and manually tune it to be in key with the synthesized kick. I try not to do too much EQ or post-processing on my kicks in general, but that's mainly due to fear of messing up my low end.

if you own a legit copy of Logic, Ableton, or FL Studio each comes with a pretty seep sample library of various drum kits. I would go through those and look for your absolute favorites, then sign up for Splice Sounds and get the 100 or 200 sample a month option (not gonna be more than $20 a month IIRC). Then start pack-diving. Instead of having to download a bunch of sample packs and remove the ones you don't like, you can now search for specific sounds you want, find the exact sample you want via audio preview, then buy it (and have it available for redownload forever).

Music Theory is a collection of the mathematical formulas of music. That's why it's not necessary to learn - it just provides the explanations for what already exists (and it doesn't even explain all of it!).

Basically takes up half the space I have to live in, but it's worth it.

One of the keys to making things sound bell-y or metallic is the idea of frequencies being introduced that are outside of the normal harmonic series for the tone. SeamlessR has a How to Synth video on this subject!

Sub always > No Sub.

That being said, I live in a 450 sq ft. studio in a building that has quiet hours - So I've been considering getting a SubPac. Anyone have experience with one?

I find myself most comfortable writing chords on a keyboard, but melodies I can go either way (though I find myself leaning towards the piano for very glidey portamento'd notes).

All my drum loops are programmed in Maschine. Kick/Snare gets dropped in on a grid, most other stuff gets played in live and quantized if needed. I don't think I could go drawing in MIDI notes on a drum rack unless I absolutely had to.

Well, here's the bad news: There's no set way. Sometimes people start with a basic chord progression, sometimes they start with a bassline, sometimes they think of a melody, and sometimes they start building up a drum loop and work on top of that! It's all about what inspires them at the moment.

Here's the good news: Every single song you've ever loved is an open book waiting for you to read. Referencing tracks isn't just listening to them and dragging them into their D.A.W.s, it's about a whole new type of analytical listening. You're no longer a fan, you're a student.  I've attached a little PDF that has a good list of questions to take with you every time you listen to a track from now on. Start answering the questions as you listen to the song over and over. Do you notice any similarities between the tracks? Are there any trends that seem to emerge? Are certain sounds louder than others? What sounds did they think was the MOST important to hear (the sounds that feel like they're on top of everything else)?

The reason why the top-level producers often hesitate to talk about this kind of stuff is because no one wants to hear "It's a lot of work." But don't worry, because there's plenty of resources online to jump start you.

I'd watch this Q&A session with NGHTMRE and this SeamlessR playlist and see if it helps you any. The MOST important thing to remember is that when you're first starting out it is quantity, not necessarily quality, that you're looking for. The only way to truly know what sounds good is to make a lot of stuff that sounds bad, after all. Every time you force yourself to make a song, you've learned something new so that the next time, that part isn't so hard.

Don't give up!

EDIT: Attaching a picture of the PDF so people can see it without having to download