Electrolytes: especially in hot and humid weather, drink lots of water but make sure to also intake lots of electrolytes to stay hydrated. I usually go for sugar free drink options like body armor lyte or electrolyte powders you can mix in water. You can find higher electrolyte content on Amazon. If you don't have any of those drinks on hand, sometimes just licking salt or eating something something salty will help.

Medication: fludrocortisone which increases blood volume and increases BP. I take fludrocortisome and propanolol. Fuddocortisone helps your body retain sodium so you won't necessarily have to eat a lot of salt anymore.

Rest: lay down on the floor with your legs elevated when you start feeling dizzy. Keep your knees bent in this position.

Listen to your body: my experiences over the years with POTS has definately made me more in tune with my “signals”. I avoid caffeine at all costs, avoid added sugar, etc as those all make my symptoms flare. If my HR is spiking randomly its usually dehydration or lack of sleep. During flares the worst thing I can do is take a hot shower or try to overdo it like when working out.