>>I like neutrals a lot, so I'll try to remember that next time I'm picking yarn.<<

Good idea. Those work well with animal prints if you're into that:

https://crochet.craftgossip.com/15-leopard-print-crochet-patterns/

>> I also have a lot of similar colours right now, so I could probably do something with shades or analogous colours.<<

That should work.

>>I have a lot of patterned tops I could use for inspiration, and some multi-coloured bracelets.<<

Excellent especially if you want to make things to wear or carry with what you already have.

>> I gravitate towards greys and red myself, though I do have a decent variety of colours.<<

Stripes or blocks of different grays -- especially with different yarn textures or stitches -- make a great contrast for a single swatch of vivid red.

https://i.etsystatic.com/5363840/r/il/5a5f04/2544753338/il_fullxfull.2544753338_tqe1.jpg

https://endlesscrochetcreations.com/wp-content/uploads/2017/09/IMG_3549.jpg

>>I usually forget about the extras, since I'm usually distracted by the pretty yarn. It's a good thing to keep in mind though for the next time I go shopping.<<

If you look in the yarn section, you may find a color wheel there. The color theory books are usually in with the other books. Or you can ask the staff.

>>It turned out great! I really liked it a lot! <<

Thank you! :D