The big problem here seemed to be that you think there's something wrong or outrageous about telling a girl she's hot; like it would get you slapped or in trouble or something. The fact is that's not true at all. You want to chat to fit girls because they're fit, there's absolutely nothing wrong with that. Girls are hot, they want to look hot, and they like to be told that provided it's not done in a weird way. A big struggle for beginners is understanding that girls all like guys and want to have sex with them.

For a girl to be comfortable around you you have to be comfortable in the situation yourself first. If you go up to chat to a girl she already knows why. Coming up with false excuses and big convoluted routines to find a way to talk to her gives off the message "I'm attracted to you but I'm not comfortable enough to be honest about it". So not only does that way very rarely work, it ingrains in your head that you have to do that to talk to girls.

Being friendly, direct and relaxed about it works a lot better, and there's nothing outlandish or outrageous about it at all. It makes your life much easier. The fact you think it's a big deal is exactly why you should go out and try it. The earlier you realise that stuff like telling girls straight up that they look hot the better off you'll be.

At least that's what I thought of this. Hope that's a help.