My theme won't give me much space between paragraphs. I'd put in extra spaces and they'd disappear. So I went looking in the forums and found lots of people have run into that problem. The suggestions for fixing it were mostly too technical for me (I guess -- anyway, when I tried them, nothing worked). But I came up with a simple, jury-rigged solution.
After each paragraph, I put in a hard return, a period, and another hard return. Then, since the background color of my theme is white, I changed the color of the periods to white. Shazam! There was my clean space between paragraphs.
I hope this idea may help someone else.