Here is my take on
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Basics of texture making in Minecraft (heavily WIP; v0.5)
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Introduction
This might be far from "beginner level" psychologically, noone starts working on texture packs (or drawing in general) with thoughts like "i have to master engineering of visual designs; great responsibility kicks in RN", i get that and it's not supposed to be a book of rules. That is to make you understand: there's more to it than you probably think, and it's better to be aware of complexities beforehand.
An issue
There's an issue with pixel art, don't want to sugarcoat it (raising awareness means eventual raise of quality). Average pixel-art piece looks like crap. This style became a shortcut for primitive portrayings - try googling "pixel art stock" - redrewed in regular style, that's child' scribbles, what's worse, it's getting saled.
Just think how highly common people tolerate establishment (in general and commerical terms) of low-effort garbage. "If something is dumb simple, it's good" (hello pop industry).
Don't get the wrong idea, i used to suck in pixel art (probably still do), well i also never tried to sell shitty 32x32 icon - aka 5 minutes of unqualified work - for 12 bucks. The idea is to git gud, then proceed to serious (no) business.
*cliches for associated traits*
*icon design for shape*
*firm stance and enstablishments for open mind and rethinking*
Here's another important point: you don't have to "agree" with original creators in terms of portraying (i'm not talking exclusively about IC2). They might be more of, say, programmers and less of artists than you. Everyone's doing their jobs; you know better.
*techniques for better looks*
I forgot the smol header name's here
So, "to make things look good" is a vague objective, of course. "...look informative" would be wiser wording, and recognizability is an important aspect of it. As a texture artist, most of the time you're portraying day-to-day things - in terms of "cultural images" (cliché[s]); say, there's rayguns in every space opera media for like 50 years now, so it's kinda molded in your brain and you don't consider it unusual, even though never seeing it in real life.
What you need is to balance between such clichés and realism depending on the context (project's general degree of realism i'd say). Well, Minecraft isn't about realism in it's mechanics, so i don't see the point of forcing it in it's graphic aspects, we can go full cliché mode here; let's try to break down a "cultural image" of Uranium from IC2 (without considering it's original looks, imagine that it doesn't have any textures at all for now) for example:
-Dangerous
How mod handles this aspect/trait:
Radioactive debuff mechanics and stuff in terms of gameplay; it doesn't in it's ways to inform a player about it, however. Generally, aside from realism (there's no "HAZARDOUS MATERIAL!!!1" labels on every piece of uraninite in real life, obviously, and so it can be in more realistic projects) where there can be zero informing, it depends on the project's internal ways to handle it. IC2 could've do it within the Minecraft's own boundaries using item descriptions (or it does that? ~2011 was the last time i've played IC2 without GT...), but you see, the developer[s] way of thinking aren't clear here - since they probably did it intendly.
How you can add to it:
Let's assume that they left it for you to solve it in artistic way, what can we do? Minecraft has enough hacks and abstractions in it to have doubts about adding some more. So, going meta and putting an icon (radioactive hazard one) right on it should do the trick.
-Glows
How mod handles this aspect/trait:
It doesn't, i don't know why though.
How you can add to it:
Since glowing is a "code thing" in Minecraft, there's no much to it; "contacting software side devs" would be it, but it isn't since texture packs aren't official.
Going hand-draw, we still can add a halo and some inner glow.
-"Acid"-colored
How mod handles this aspect/trait:
it doesn't and it's not supposed to, here's your job actually kicks in since this trait is completely about visual features.
How you can add to it:
Make it "acid"-colored, of course. But in this case, drawing it dark would be a better option to point out that it's raw and not in it's "full power".
That's what we have with it. I didn't want to do it very precisely, just a 3 min sketch.
More things:
*Consistency;
*Style;
*Uniqueness;
*the end blahblah*
. Sorry 'bout that.
.