I am currently soldering a new Analog Axis for a friend and the tin to help ground the solder to the joint has burned off and now the tin either goes to the tip or the solder itself. I have no idea how to get the tin to "stick" to the board now. Any help would be very appreciated! Thanks
As others have said, make sure your soldering iron tip is clean. Use a damp sponge or paper towel and wipe off any old, burned flux. Once you've done that, make sure you're using solder meant for electronic soldering. I use 60/40 solder with rosin core flux. Adding rosin flux to the connections you are trying to solder will help the solder flow onto these parts more easily. Do not use acid core flux- that's for plumbing.
Put a coating of solder on the parts you want to join. Make a mechanical connection if you can (twist wires, etc...). Heat the joint, not the solder. This helps eliminate cold solder joints. Don't move anything until the solder solidifies.
All of these suggestions are best practices, but sometimes 'good enough' is, well, good enough. There's a number of howto guides on the net- here's one.