Keep in mind that magnesium transports potassium into the cells. So, you can go hog wild on the potassium, but without enough magnesium, it's not doing you much good.
With that in mind, boost your eating of high-magnesium foods. You can use the
USDA's Nutrient List web page to rank foods by mineral content. Spinach is a big hitter (157mg/cup), as are pumpkin seed kernels (151 mg/oz (142 seeds)), white beans (134 mg./cup), and halibut (85 mg./5 oz.). Go easy on the halibut, though, if you're thinking of having kids; samples tested by the USDA contained a fair amount methylmercury. If you can work coconut milk (41 mg./oz) into some recipes (like a protein powder shake), you can up your magnesium some more (not to mention healthy saturated fats).
Once you're chowing down on these foods (or taking chelated magnesium supplements), you can gulp some
potassium broth. At 750 mg/cup, that's not shabby. Just in case it freaks you out to think of taking that much potassium in one sitting, don't worry. Michael Murray's Encyclopedia of Nutritional Supplements says that although potassium salts can cause nausea, vomiting, diarrhea, and ulcers when given in
pill form at high doses, these effects do not occur "when potassium levels are increased
through diet alone (emphasis mine)...Therefore, the best course is to use foods or food-based potassium supplements to meet the human body's high potassium requirements."(1)
(1) Murray, Michael, N.D.
Encyclopedia of Nutritional Supplements. Rocklin; Prima Publishing, 1996; p. 179.