When I was living in Taiwan, one of the ways I forced myself to remember to pronounce the tones distinctly was by waving my hand in front of me, tracing the arc of each character’s tone.

It helped a lot even if I did look like an insane expat conducting an invisible orchestra.

One more thing: there's quite a bit of variation in how regional accents in the mainland can affect tonal pronunciation. It might be worth reaching to some native speakers to give you some baseline figures.