some recipes I use produce a satisfyingly mounded muffin, some a disappointingly flattish one (though still delicious). What makes the difference? Is it just a matter of adding more baking powder to the batter? More batter to the muffins cup? Or it is some complex formula of batter thickness/thinness, the degree to which the eggs are foamy, the acids and bases interacting in the recipe???
Do you know?
Add pot.
There, the rest of the thread may now be productive. 
My personal experience has been more batter = higher muffin/cupcake. Most recipes I’ve seen say fill the cup 2/3 full - I tend to do 3/4 full.
I’m not a professional baker, but I’ve never had any complaints about my baking.
I’d have to see your base recipe to be able to say. Also, are you talking about muffins with fruit or vegetables added? That can affect the rising.
I don’t know if it’s indicated for all varieties of muffin, but I have one corn muffin recipe that says they’ll be higher if you let the batter stand a few moments before spooning it into the pan.
With cake I was always told incorporating more air made it lighter/higher.