Spawning Location
When you first spawn you'll notice some text show up on the right side of the screen. This will contain your general location, so make sure you remember this. Unless you spawn near a landmark, it's the only way you'll have any idea where you spawned.
Map & Compass
There is an in-game map, but it's an item like any other. Until you find one and store it in your inventory it won't be displayed when you press M. However, there is an online version of the map, which also contains the English names of locations. Towns will have a sign containing their name somewhere near their borders, but it will be written in Cyrillic.
There is also an in-game compass, usable with K, but like the map is only usable if you have a compass in your inventory.
The map and the compass are the most important tools at your disposable for figuring out where you are, and what direction you need to walk in order to get where you want to go.
Night time
I haven't tried this method myself, but apparently there is a way to locate the North star at night. If you find yourself wandering around alone at night this should prove useful in helping you get around.
Finding Action
Towns are the best place to find zombies and players. Zombies have a much higher spawn rate in towns (in fact they currently don't spawn in the woods at all, only near buildings). Towns are also a required stop for most players since contain the most loot. Your best bet for finding a town after you spawn is to just follow the coast in either direction. It may take some time, but you'll eventually find a town.
Something else to pay attention to is the in-game chat (by default you talk with "/", and change channels with "."). Watching this is one of the best ways to find out where players and zombies are. Players will often send messages looking for people to meet-up with, or give out warnings if their are a lot of bandits or Zombies in an area.
Repairing Vehicles
Vehicles are repaired by using the replace parts option accessible through the action menu if used on a vehicle.
Only some vehicles can be repaired (list below), and in order to repair them you need to replace all the broken/missing parts in the vehicle (list below). Every vehicle starts missing all of their parts, but it is possible to come across partially repaired vehicles (due to the work of other players). In order to replace parts you require a toolbox, and after the vehicle has been fully repaired it must be filled with fuel via a Jerry Can to work (the amount of fuel required depends on the vehicle).
Repairable Vehicles
Land
GAZ
Offraod Pickup Truck
Pickup Truck
Military Offroad
Motorcycle
ATV
Air
UH-1H Huey
Sea
Fishing Boats
Required Items
Engine Parts
Fuel Tank Parts
Four Wheels
Scrap Metal
Windscreen Glass (optional)
Toolbox
Jerry Can (amount required varies based on the vehicle)
Best Answer
The only information I could find on the subject is the DayZ Wiki Vehciles page where it states
(emphasis mine).
As I understand it a vehicle spawn point will never spawn a new vehicle as long as the existing vehicle is in use and has not been destroyed. If the vehicle is destroyed or left unused for 7 days then I believe that the vehicle will respawn after the next server restart.
I'm not sure where the vehicle will respawn though - I have heard that vehicles can also spawn either at their original location or at the point where it was last saved, repaired or even where it was destroyed. If this is the case then it implies that vehicles are probably never going to be found at their original spawn point.