The most important element of putting up food is safety. While problems like botulism are rare, they can be serious. Please make sure to follow recipes exactly, as the amount of acid, cooking time, and temperature can determine whether foods will be safe to eat.
The type of food preservation you'll do depends on your storage space, what you like to have on hand to eat in the winter, and how much work you want to do. Freezing food is the easiest method, but it depends on whether you've got extra space in your freezer.
For excellent over-all advice and recipes for canning, freezing, and otherwise preserving food, visit any college's Extension Service website, or:
A brief rundown of what I do most years:
Canning is a great technique for preserving high acid foods like tomatoes, fruit, and pickles. For a thorough explanation of canning, go to vegetablegardener.com. This will give you a very clear introduction to water bath canning (non-pressure canning of acidic foods). The ones that I do each year are tomatoes, peaches, and applesauce.
Simple Tomato Sauce: wash and cut up tomatoes into halves or quarters. Then pulse in food processor until they are chopped up well and the skins are pulverized. I usually do a few batches at a time until I have about a gallon of soupy tomato sauce which I then cook down for several hours over low heat until the desired thickness is reached. Salt to taste. This can then be canned or frozen. I doctor it up with herbs, garlic, etc when I use it in the winter time that gives me more flexibility.
Tomatoes can also be frozen whole and raw by placing them in a zip-lock bag as they ripen. When you later need to use them, you just have to run them under warm water to slip the skins off.
Roasted Ratatouille: I chop up onions, zucchini, eggplant, and tomatoes and toss them with herbs, olive oil, and sea salt. I then spread it on cookie sheets in a single layer and roast in a 400 degree oven until soft and starting to caramelize (turning once or twice helps). It takes about 50 minutes per batch. I then freeze this in containers or freezer bags. It is fantastic on pizza, pasta, in lasagnas or other casseroles, or on its own.
Sweet Peppers: just chop up raw peppers and place in a freezer baggie. Very simple and a great addition to just about anything you are sauteeing.
Herbs: any herb can be turned into a puree with a little olive oil and salt in the food processor. This is a good candidate for freezing in ice cube trays and then placing the frozen blocks into labeled baggies. When making dishes in the winter, simply toss an herb cube into the pot for extra flavor ; soups, sauces, stir fries, salad dressings are all good options for this method. Pesto can be frozen this way too, allowing you to thaw out just what you need.
Other vegetables that freeze well are green beans and spinach: just steam, dry well, and place in bags. You can also chop spinach or other greens after blanching briefly, and press into ice cube trays to freeze into cubes to have on hand for soups, pasta and the like in the winter.
Pickling beets, carrots and cucumbers is another simple and satisfying way to store these veggies, either in the refrigerator (for consumption within 3 months), or by canning them for a longer shelf-life. See recipes at: