You can get these tools at your local Home Depot or hardware store for around $30 - $40. Batteries and Deans connectors are available at Fox Airsoft.
Start off with your basic Tamiya connector on your stock battery. You might have a different connector but a Tamiya is pretty standard across the Airsoft industry.
Use the wire cutters to cut the wires to to your desired length
Use the wire stripper to strip about a quarter inch off the end of each wire.
It should look something like this when you've cut ands stripped the wires
Add some solder to the end of each wire as seen here. The goal here is to fill the wires with solder for ease of connection.
Use a small clamp to add some solder to the deans connector.
IMPORTANT: Slide your heat-shrink over the wire BEFORE you solder the connection.
It should look like this before you solder the wires to the connector.
IMPORTANT: Notice the positive and negative markings on the connector. Red is Positive.
Connect the wires as seen here. Be careful while soldering.
Slide the Heat-Shrink over the connections.
Use the lighter to lightly kiss the heat-shrink to get it to wrap tightly around your connections.
Bam! You're done. You now have a deans connector on your battery! Don't be a n00b, deans your gun and batteries for less resistance and increased trigger response.