Doing apple sauce it works better cooking the apples first.
When doing peaches don't let them get to ripe.
These peaches got a little too ripe before they got canned.
Before you put any food in the jars make sure that there are no cracks.
Make sure that your jar does not have any cracks around the rim too. If they have cracks it will not seal.
Be careful to not use your seals more then twice. If you do it will not seal right.
Some times ti is safer to use your seal only once.
For strawberry jelly if you do not want to use as much sugar freezer jam takes less.
For any kind of canning make sure you fill the jar to the right measurements.