If your soldering looks like this, you've come to the right place. This has just about everything bad. Both joints are cold, too much wire is exposed and the insulation on the red wire is seriously damaged. This could very easily blow a fuse when the motor is activated, even during a match.
Both of these joints are cold. Note how the solder doesn't flow evenly over the wires. Another thing to note is how close the black wire is to the other terminal. Although this is OK as is, be careful when you solder on the other terminal so you don't damage the black wire's insulation.
The solder doesn't flow onto the wire or the terminal.
The black wire is a good joint. It is very shiny. The red wire could use a little more solder.
This is good connection with the previous large motor. Note that the wire's insulation end very close to the terminal. There are no big globs. Be very careful here since excess solder can short the terminals to the case and blow a fuse.