Grinding my own beans before every cup is the biggest game changer for me.
If you are considering getting a grinder, the best "budget" bur grinder I've used is the Baratza encore (ESP model). I put budget in quotes because it's still expensive IMO, but a good value for under $400
Edit: and I use an Aeropress to actually brew my coffee (using the inverted method)
TIL about data poisoning!