- Get a good hot soldering gun/stick (55W+). The hotter it gets, the less time you need to melt the solder (the items you are soldering can absorb a lot of heat if you heat slowly...and it's not good for batteries). Turn it down inbetween things if you need to fiddle with stuff for a little bit (helps with oxidation/scaling). A wet sponge is good for cleaning off extra solder from the tip...I use a wet cotton rag balled up and just swipe the tip when I'm done a joint.
- When doing exposed connectors (like DEANS)...I've gotten into the habit of doing one wire (tin connector, cut/strip/tin wire, position shrink wrap, solder connection)...then doing the other one. Pretty much dummy proof so you can short the battery.
- also, before I do the other wire, I'll position the shrink wrap of the first wired and shrink it into place....that way, even if you slip or happen to touch the bridge the connection with tip of the soldering gun, you probably won't short anything.
- tin both the wire/connector separately...then melt them together. Too little is no good...but you don't need blobs of solder though.
- as long as you're not going to short anything (i.e. do one at a time, protected by shrink wrap), you can file the joint a little after you're done if you have any spikes/bumps that will cut through the shrink wrap.
- using the other end of the connector is a good tip
- if it's not working well...you can always stop, regroup and try again before you start melting stuff (i.e. shielding, connector bodies).
Get extra stuff (wire/connectors/shrink wrap)...practice making a couple for charger extensions, size converters (i.e. DEANS to Large, Large to small...really handy for emergency situations at games), etc... By the time you're done those, you'll be more than ready to do up your gun.
Best of luck.