You don't normally need to stand to pedal uphill. It's a pretty special case thing. As you get to be more comfortable with riding, you may *choose* to stand. Also depending on your size, you may be dealing with a twitchier bike than a lot of guys are riding. While I'm not teensy, for a variety of reasons the right bike size for me is about a 48 or 50cm. Some bikes in that size range might have head tube and seat tube angles like 70/75, and generally bikes are a bit more stable when the angles are 72/72. With a twitchy bike, you need to have better biking form in order to stand or ride no hands. There's other stuff that goes into twitch, like how long the chainstays are and how prone the front wheel is to flopping to the side... all kinds of little details. But it's harder to look like you've got mad skills with a twitchy bike.
You don't have to signal turns. If you're not comfortable taking your hands off the bars, you can stop and cross the way a little kid would, as a pedestrian. It's annoying and kind of a pain, but it works. Sometimes I signal, sometimes I cross as a pedestrian. I pick and choose depending on how tired I am, how heavy the traffic is, how many lanes the road is and so on. Heck, sometimes it can be as simple as I decided to get a drink while waiting for the light to let me cross.
You develop grace by practicing. That means you spend a fair bit of time being sweaty, red faced, and looking vaguely dorky
. Most everyone who is good and fast has been there themselves, so they wouldn't dream of making fun of you. (and realistically, I can't help but look a whole lot dorky whenever I ride, since my bike is a step through granny bike
) You'll find that most times if someone is rude, they don't ride themselves, or they're new and still trying to get comfortable with embracing their inner dork.