A couple of things I've learned over the years about canning:
If you are canning things that are high acid (most fruits, tomatoes, and pickles), a water bath system is fine. There are charts available from your local extension service (
like this) that will assist you in determining what is acidic enough to can, and the times needed to ensure safety. I think the Ball book has already been mentioned - another good resource.
Don't cool jars upside down. It can interfere with the seal (that is the old-timey way for jellies - fill with hot preserves, cap, turn upside down.
Don't do it. Use a water bath and keep them upright.)
Make sure your cooktop can handle a pressure canner if you use one. Most glass/ceramic cooktops instruct you not to use a pressure canner as it can break the top (combination of the weight and heat).