Switch to soap bars! Nowadays you can find cruelty-free, vegan, pacakaging free soap for almost anything: body, face, hair and even deodorant sticks that look like soap (*cough* LUSH *cough*)!
Rather than buying shower gel/shampoo/bubblebath, etc wean yourself off the plastic bottles and stick to soap (and even bath bombs for the extra bubble). Lots of brands can be found pacakge free, or at least in cardboard boxes!
(Even soap in plastic wrappers is technically reducing the amount of plastic waste, unless you reuse the bottles of course!)
To push the boat out even further you could have a go at making your own!