Good. I have no idea if the following is a good technique, but it has been working in my family since before I can remember
Basically, just make your sauce how you normally would. The only cooking requirement is that it simmers at least 10 minutes to kill the bacteria.
Meanwhile you're going to either bring a big pot of water to the boil, or just use a kettle a few times.
Place a metal spoon/knife (or anything metal) in each of the jars and fill them with the boiling water. The spoon stops the glass from shattering due to the heat. Also pour some of the water onto the inside of the lids and your ladle (and funnel if you have one). i.e. sterilise everything.
Let them sit for a few minutes (or until your sauce is ready) and then pour out the water, hopefully without burning yourself. Place the jars upside down on a clean tea towel until you're ready to fill.
Fill 'em up to within half a centimetre or so from the top. I can't recommend a funnel highly enough.
Clean up any spillage on the jar and screw a lid on fairly tightly.
Repeat for all the sauce.
Leave your jars to cool. Whatever you do, don't touch the button on the lids. The next day, have a look at the lids. If the button has popped down, it has sealed. You can store those for months in a cellar or pantry. The ones that haven't popped aren't sealed and should be kept on the fridge and eaten within a few weeks.
As I said in a earlier post, if you use more sour tomatoes or add some lemon juice it will keep better. I assume that acid kills bacteria or something like that.
You'd also probably have a better success rate by canning in a hot water bath, but you need the right kind of jars and it's more of an effort.