Fridge pickles are a classic GikoFood that couldn't be easier to make. Low calorie, nutritious, cheap, and tasty. It takes about 1 weeks of brining to finish pickles, and in theory they could be good for a month or two, especially if there's more vinegar/salt/alcohol.
How exactly you wish to season your brine is left up to you, but the basics are that you want to achieve at least 3% acidity (generally accomplished with 1:1 of 5% vinegar to water, but some vinegars are more acidic!) and a couple tablespoons of salt.
You could be crazy and skip out altogether on the water but that'd make the pickles too sour and it'd probably be gross. Some people like to use apple cider vinegars and things but that seems weird.
I like to sub out some of the water for GikoShine, giving an extra little kick to my fridge pickles. Whether vodka or gin, they can really help with preserving the food... that's the point of the vinegar and salt, aside from the flavor.
I also add a dash of MSG and various powdered spices -- pepper, ginger, cloves, nutmeg. The brine will naturally pull flavor from whatever foods you throw in, but if you have powdered spices on hand, they can amplify the brine as well.
If you got a sweet tooth, add sugar; it can help counteract heat and acidic flavors, if they are undesired.
Making fridge pickles is not an exact science besides adding enough vinegar and salt to counteract mold; practice makes perfect. Experiment! I tend to re-use brine 2 or 3 times, supplementing with salt and vinegar before adding new vegetables. If the flavor is leaning someplace I don't like, I'll pour out some brine and try to push the brine in a different direction.
Everyone hears pickles and thinks cucumbers. And cucumbers have deserved their reputation for this: they suck up the brine great. You can cut them like coins or cut them the other way, as spears; both are great! You want cucumbers as fresh as possible, else they'll be kind of soft and mushy.
If you cut the cucumbers into ... small BiteSized chunks ... you can later dry, bread, and deep fry for some delicious homemade FriedPickles. These are criminally tasty.
In addition to cucumbers, other vegetables take very well to pickling. My GoTos are carrots, garlic cloves, onion, sliced chili peppers... I really don't think there's any wrongs here! Carrots can be even better to munch on than cucumbers as they stay very crunchy. Dill is a classic herb and many other herbs go well with pickles, but availability differs by region and season.
Boiled eggs are also terrific pickled. However, after pickling eggs, it's best to dump the brine and clean the jar. Like with vegetables, you want to brine them for about a week. Important note: make sure there is no yolk exposed when adding pickled eggs to the brine, or it'll dissolve and make it gross.
Soaking chicken breast in fridge pickle juice is also a great cooking technique: it adds a lot of good flavors and moisture to the meat, helping tenderizing it. Like with boiled eggs, dump your brine and start anew after brining meat!
Throw a good couple of tablespoons of salt in the bottom of your jar, along with any spices; fill the jar up maybe 30% of the way with vinegar, then fill to 60% with water and any GikoShine you wish to add. Screw on lid and shake that good to make sure everything mixes together.
Keep a note in your NoteBook about what ingredients and ratios you've used. As you make more fridge pickles, you'll start to realize how to increase or decrease the presence of vinegar, salt, and seasonings. After you make enough batches, you can just eyeball it and go with your gut on how much of ingredient X or Y are necessary.
Chop up your chosen foods to appropriate amounts, throw them in the jar, screw lid on again, shake good. If there's any head room left, add water, vinegar, or gikoshine, and throw in your fridge for a week or so.
And that's all there is to it!