Cyrus - The basic steps of capturing a WPA handshake are as follows:
1) set your card in monitor mode
2) airodump-ng on target channel, filtering on target BSSID, and writing capture to a specific file
airmon-ng start <interface> <target channel>
Note: It's important that there be a client associated to the target because to speed the collection of the WPA handshake you're going to deauthenticate the client and capture the WPA handshake when they re-associate. Otherwise, you're going to be waiting until a client associates to capture a WPA handshake.
airodump-ng -c <target channel> -w <capture file name> --bssid <target MAC> <interface>
3) deauthenticate the associated client (I like to use a deauthentication packet number of 15)
4) once you get the WPA handshake, stop airodump-ng and run aircrack-ng on the .cap file using one of the test password files or John the Ripper
aireplay-ng -0 15 -a <target MAC> -c <associated client MAC> <interface>
Note: make sure you include your passphrase (Whitew0lfe@2083) in the test password file, otherwise you won't find it. There are a couple of test password files included in BT4 (look in the /pentest/wireless directory.
aircrack-ng -0 -w <path to password file> <your capture filename.cap>