First off, please don't think these ramblings are meant for the 'getting to know you' phase. If a Chick is that worried about what yer thinking early days...run for the hills and fast! She's a bunny boiling stalker...proberly.

Short term Fun = attraction of some sort, decent personality (funny) and good shag. End of. I'm pretty sure we can all agree on that.
However, I'd like to believe that at some point you might knock across a long term relationship. This is mainly what we're covering from a female point of view. Hopefully it'll help the male population of blonde figure out what makes us tick. Likely? Dunno, but here's hoping. If any of you DO get it, please spread the word to the rest of your male friends.
_______________________________
Honesty....hmmm. That's a tough one. We'll give it an ol' go and see how we get on.
Here's the thing. I don't care what any woman says. With females, honesty is mood based. If we're in a pissy mood (for whatever reason) it's probably not the best time to come out with, "Your bum (belly or whatever - pick the body part of your choice) looks huge in that outfit." Not if you want to live anyway.
I don't care if you're in the shop with her and she's looking for a second opinion, or it's already been bought and she's trying it on for you after the fact. At this point, something more along the lines of, "It's not cut right and just doesn't suit you. I think you look much better in (chose something you like that she's worn before)."
This saves you on two fronts. If you're trying to get ready for a night out, she's already worn the other outfit before. She already knows what goes with it, hence you get out the door faster. Bonus round - You've insulted the makers of the outfit, not her.
If she's in a reasonable or even light hearted mood, you MAY get away with saying, "Yer bum looks huge in that!" but be sure to say it with a hint of a giggle so she won't revert back to pissy mode. Simples. See?
If dinner is crap, but she's spent hours preparing and cooking it for you, it's best to try and pick out at least one small thing you liked (if possible) besides saying dinner was crap. We don't need you to tell us the roast was over-cooked or the gravy didn't come out as well as last time. We already feckin know that and are berating ourselves quietly over said facts. Don't add fuel to the fire! Best bet after she's worked so hard and failed miserably is to offer help doing the washing up. She just wants it to be over and tucked up with a glass of wine on the sofa...now. lol
It's the little things Lads. They may seem trivial to you, but if you want to keep peace they aren't rocket science to master. Honesty is very important, but doesn't have to hurt.
PS Irrelevant to this particular section, but I'll throw it in anyway - Not all Chicks hate sports.