With things like a heart it sometimes seems simple to draw but truth is if I want to do it right I start with a draft and I keep remodeling until I think it's the right shape. Than I draw the lines with my pen and I erase the rest. I also notice that the more I draw the same things the easier it becomes for me like I have a book full of thick lines in my head. That is also how I see things I want to draw, thick black lines. A photograph, a color page, A plant, I turn every item in my head to lines and then I start to draw. Back to the heart, I always draw the right side first. I just tried it to be sure, even a flower I start on the right side most of the time.