This sounds ridiculous to some, but I have learned quite a bit about Life just by gardening. Some things live and some things just don't, but there are some basic rules about what you do in the garden.
Soil. A steady base, with good drainage and room to grow as far as you need. (This could be a sticky wicket.) Not all plants need dirt, but a steady place to put their roots. Plants need good soil, you cannot grow an orchid from the dirt you've been pouring your old motor oil in. It is important to keep your soil free on contaminates and watch the amount of negative content gets in.
Food. Not exactly fertilizer, this is the other stuff that your plants eat, at a much smaller level. There is nitrogen and hydrogen and oxygen, and carbons and lots of other lovely things. Well, they are lovely if you are a daisy. Sometimes, these things such as worm poop, or even a nematodes corpse, could be as delicate as a crisp salad with flower petals or as sturdy as a peppercorn rubbed steak. Nourishment needn't come with a big extravagant meal, just a small snack can sometimes provide all you need.
Water. About this time every year, my skin has been just a little bit drier than it was last year. My skin is amazingly dry. One of the reasons is because I go out and stick my hands in the dirt a few times a week. Just to make sure there is enough moisture out there. Living in any environment you live in you must absolutely give enough water to the plants. I lived in Oregon for years, I had a lovely cactus garden that sat in my dining room. I never watered it, it was able to get what it needed from the air surrounding them. This is not the case when I tried to keep a few "Air Plants" alive. Balance is very important.
Weeds. Let's face it, there are things that grow out of the ground that have pointy things in them like like to poke you in the feet and ruin your favorite sweater. But if Man had pulled every single thing that had points on it, we would never have the patience to watch a rose bloom. Or anything as tasty as blackberry cobbler. Perhaps we are too impatient with weeds, there is a reason for them, in the first place. They could just be holding the dirt in place.
Poop. Well, not one of Life's best topics, but lets just hold hands for a minute. Shall we? Poo gives the plants something to chew on while they bide their time getting big and strong and making you a lovely pumpkin for Halloween. Fertile ground is important, gives the mind something to do. Never be afraid to experiment with fertilizer, you may just find the perfect one, by accident.
Light. Every day has a certain amount of lightness and darkness to it. It is the balance of the planet, you cannot fight it. Wake, sleep, play, rest. Okay, you can fight it inside you, but it is as unhealthy as trying to grow moss in the desert. When you are gardening there is little you can do about how long the day is going to light. The plant knows. That's why the crocus and the hyacinth pop their pretty faces out before the last snow melts. That is also why certain things just will not grow if they don't get the direct amount of daylight, or darkness.
Finally, you must, absolutely must, just give up on some of your favorite plants, because they will not come back every year, no matter what hocus-pocus you do. Others, will come back over and over again, no matter how many times you dig them up, burn them or throw them away. Those little determined things, are called 'Family'.