People always tell me to connect my lines, but I don't really know what that means, can someone help?
You don't have to connect your lines always. Sometimes it looks far better when you don't. In this case if it looks terrible when you connect your lines don't do it. You should give(post) us an example.
Yeah I can see why people are telling you to connect your lines, it could still look cool if you did dotty lines and it'll also be a interesting style of detailing. The issue is the short lines(black lines) seem random especially with the grey lines. The grey lines actually give shape to the rock, re-outline the grey lines with black.
Is this alright? (It's not finished down the bottom just yet) I drew it ages ago but I thought that I would continue with it