Great answers here.
I think the best approach would be to follow some good basic principles and then ask a question if you run into some difficulty. For example, you ask about gaining respect, but respect can be lost in many ways, and each situation requires something different to get it back.
The best principles of leadership IMO are:
1. Lead by example. That doesn't mean doing someone's job for them, it means that if you want them to work hard, work harder yourself first before you bring up the issue. If you want them to follow rules, follow them yourself before you bring up the issue. Everything that you want to reinforce, show that you do it first. This will prevent almost all problems with authority.
2. Be consistent. Don't enforce something for one person and then not enforce it for another, regardless whether one person is being a jerk and the other is not. The goal (and this is the same as 1.) is to create a system where people know exactly what they should be doing, what will happen if they don't do it, and don't have any clear excuse for not doing it.
3. Don't be quick to make issues out of things, but don't stop moving forward toward a conclusion. Show restraint, make sure you didn't miss something, and be nice first (people are watching), but don't let something go that isn't resolved. Being under good leadership is a question of pressure that, when you're doing your job, propels you along and even motivates you, but when you try to stop, it gradually and consistently builds until you have to keep moving or get out.
4. Don't be too concerned with 'being a leader'. A busybody manager is not one that people generally enjoy working for. They want someone who is simply able to face problems, evaluate them, and give instructions that turn out well. Focus on that first, and you will get the respect of capable people with good character, who will also help you resolve problems (sometimes without you even knowing it).
