I think when it comes to rules, they are more like guidelines in order to ensure that you're really dressing the style. There are things you can tweak here and there to suit your needs. But after so much tweaking and bending it reaches a point where it's no longer Lolita. I mean, you would wear a pink my little pony shirt, a pastel tutu, a pair of ugs, and spikey choker then call it Goth. It would be an interesting fashion statement, but not the style that you are claiming it to be. Same goes with Lolita, I think.
The rules I follow are:
Silhouette: Meetups and conventions get my huge petticoat, if I go casual for everyday I go with my lighter Bodyline petticoat and a skirt, or no petticoat and a simple jsk/cardigan/bolero combo. I don't feel comfortable in a huge petticoat if I'm going out to dinner or going shopping. But I'm fine in a printed skirt and a nice top.
Modesty: I dress modestly anyway, and I'm not comfortable unless my shoulders are covered. I prefer to wear tights or OTKs.
I also try to make sure that I look well put together: hair or wig neat and styled. (usually my real hair for everyday, and I usually curl it and put more effort into it than usual.) I wear makeup, because if i put all this time into dressing nicely, I feel plain without makeup (plus makeup is fun). I try to keep colors and themes matching. I also make sure I have something on my head, usually a headbow, but if It's everyday, I wear headbands usually.
At any rate, I try to make myself look nicely dressed either way. I wouldn't wear dirty sneakers and greasy unkempt hair with pretty and expensive clothes. But that's just how I feel about myself.