How do I align a wheel? I broke a couple of spokes on my wheel, now it's all bent, how can I align it back again? What kind of tools do I need to do a good job?
First, replace the missing spokes with properly sized spokes. 

Next, on the drive side of a rear wheel with derailleur gears you will need to remove the cassette, insert the new spoke(s), then replace it. That requires a special tool (there are several variations for different cassettes and freewheels). A bike shop can do this or sell you the correct tool.

You will always need the next special tool: a spoke wrench that fits the size of spokes you have.  

While a truing stand is great, you can do some basic truing of a bike with rim brake by simply putting the bike on a stand. With disk brakes a cable tie round the bike frame or fork can be turned so the free end is almost (but not quite) touching the rim. Anything similar will work, you just need something close to the rim that lets you see the gap between that and the rim.

Let the air out of the tire.  Air pressure in the tire will push the tube against the turning top of the spoke head, and can puncture the tube.  Spin the wheel slowly and watch the space between the rim and the brake pad.  When you have found the centre of a an area that is listing to one side, use your truing wrench to loosen the spoke nearest to it on that side ¼ to ½ turn, and tighten the spokes on the opposite side an equivalent amount.

As long as you work in small steps and work slowly, it is safe to play around and figure out how truing works.  Patience is required.  

If the rim itself is bent, it may be hard or impossible to true.