Hi Wynn,
My heart goes out to you. When I fully converted to electric many years ago I was "solder challenged". I was always worried that my soldering would be the "weak link" in the planes systems. A friend told me to get some scrap parts and practice. This was good advise and now I find it very easy to solder and have not had any failures in over 9 years of flying electric.
There are many "How To" articles on the web. Like Alan said, pre-tin is the most important. Your 25 Watt iron should be more than enough if you pre-tin both parts.
RE: the Deans Ultra Connectors, I have very good news! Go to your LHS and buy the end connectors that are made just for the blades on the Deans. They have a slot in one end and a female tube in the other for the wire. They are a perfect fit and make the job safe, neat and "easy". Your LHS may have them over in the RC car section. MPI makes them as well as other manufactures.
Another easy solution that I used before the above connectors became available is buying the pre assembled deans with wire extensions. It is much easier to just solder two wires together and avoid the deans plug. Here is a link for these. I think this link will also have the connectors too, call to ask.
http://www.hobby-lobby.com/charger_lead_with_deans_ultra_connector_302_prd1.htm?pSearchQueryId=190084
I'm sure you already know this, but just a reminder to all. After you solder the red wire to the deans plug you "must" cover it with shrink tubing before you try to solder the black grd wire to the other spade of the deans. I then place a large piece of shrink wrap around the whole deans and about 1" down the wire to protect everything and this "soft" shrink wrap makes it easier to grip the plug while unplugging it from the male Deans.
Good luck and welcome to ECL. Your efforts will be rewarded with all the benefits of going electric!
Regards,