>>2224259First off I just want to say that I've seen some ecchi style images in /c/ and some /c/ style images here in /e/. I just kind of wanted to throw that out there
Now for the picture, I wouldn't really change the size of her breasts. The boobs could be bigger all you want but that doesn't really make it ecchi style. You can leave her breast size the same if you wanted but make the shirt strain and nipples poke through the shirt, that would help. Sweat could help too but you said you don't like that. If you were okay with it though, making her shirt wet could look good. This is a bit less likely but showing the rest of her body would help and have her wear some kind of panties or bloomers. Shortening the tank top to where it ends directly under her breasts might help too.
Of course, that's just what I think.
