Cap strawberries, and peel/pit peaches. If the peaches are ripe, the peelings should pull off pretty easily. This can be made even easier by blanching peaches in boiling water for 60-90 seconds, then plunging into ice water to stop the cooking process. 

Crush fruit, or use a pastry blender, bench scraper, or other tool to chop finely. 

Add lemon juice and fruit pectin, and stir until fully combined. If your fruit is underripe and not juicy enough, you may want to add 1/2 cup of water to keep it from scorching.

Heat over medium-high heat to a full rolling boil. 

Add sugar all at once, and stir until dissolved. 

Bring back to a full rolling boil that cannot be stirred down, and boil for one minute. 

Remove from heat and skim off any foam that has formed on top. You can save this in a bowl or jar to use later, but it’s not appropriate for canning because of all the air bubbles. 

Sterilize 8 half pint jars, or equivalent, with their lids and rings. 

Fill a water bath canner half full of hot water. 

Ladle jam into prepared jars leaving a half inch of headspace. 

Wipe rims with a paper towel or damp cloth to remove jam drips, and screw down lids and rings firmly. 

Place jars in prepared canner. Fill with more water if needed to reach a depth of at least an inch above the jar tops. 

Cover with lids, and bring to a rolling boil. 

Boil ten minutes, and remove from heat. 

Let canner cool at least 10 minutes before removing jars. Cover jars with a towel after removing, and keep covered until jars have fully cooled. 

After 24 hours, check for seals, and if needed, wash jars (mine always have mineral build up from being boiled in hard water).

Store in a cool place out of direct light