If you would like to make plant extractions, the best way is to get a chemistry still to distill things, you just make a tea and boil the tea away to the other side. You can use this to boil Banana peels, Lemon peels, Cinnamon, Lemon Grass, Roses etc and get essential oils.
Dry Extraction can be done if you have a metal screen. Most hand Grinders have this built in, and the plant material has most of the essential oils left in it after this process. This process is only really good for things like Marijuana that have trichombs you can do things with.
You can also make "Solvent hash" which is usually more crude, but it has the ability of extracting more. You can actually put plant material in a still, then extract it with solvents and still get things. Solvent extract will usually get plant material too though, which makes the end result less desirable. But this can be used on everything from tree bark, to grass, to leaves, to flowers, to cacti, to fungi. This is usually poured through some type of coffee filter or cheese cloth or even paper towels to keep plant material out. Some solvents can catch fire, so if you do this, don't do it indoors or while smoking. The solvent will have to evaporate, and different solvents evaporate at different rates. The faster the evaporation, the more flammable it is.
This is how (without the evaporation step) Absinthe was made in the past, which was and is a wormwood Thujone/Full spectrum extraction. Some artists would put opium in their Absinthe to give it more of an effect. If you do this with Marijuana, you get a tincture.
You can do a water extraction, then use the same material for a solvent extraction. These extractions are usually done with a Mesh bag with a Micron above 25, but below 300. You can even use multiple bags and get multiple grades. Bubble bags or Wacky bags or one of those are what Marijuana hash is usually made with.
Butter and other oils can also be used to extract things from plants, but again, you can use the leftover plant material in water or solvent extractions still. People use this method to make Marijuana cookies and brownies, and it can be used for other plants as well.
If you do this with Glycerin (available at Wal Mart) you are making vapor oil.
BHO, Butane Hash Oil is probably the cleanest form of Solvent Hash, but Butane is extremely flammable and evaporates extremely fast, especially if it is in a Hot water bath. This is made by putting plant material in an airtight space, and spraying butane through it. The Butane extracts the essential oils, then comes out through a filter. If you put lemon grass and Marijuana in the extractor, you can get a mixture that allows you to use less hash to get your medicinal effects. Unless you need clinical grade, then that is the opposite of what you need. My brother died because doctors were scared of Marijuana, he was 10 years old and they thought it was too dangerous to give him Marijuana, and now he is dead. But if we had a pure extract in a bottle a doctor could put in a syringe and stick in an unconscious patient's arm, knowing it is clean and clinical grade. What I am showing you is medical grade, not clinical grade.
CO2 is how you make cleaner, safer BHO. Same method, but with CO2 canisters.
Then in India what they do with their Marijuana leafs and stems is let them sit in milk, then strain it out. And drink the milk, and since milk is on the Ph scale, it can extract at a VERY weak rate.
You can also "Polarize" the contents of some plants to make it even purer. You have to learn about Alkaloids to do that though, and know what to buy for the one you are using. People use Turkey basters, or gravy pourers, or the put it in their bong and blow instead of suck. Because once they naturally separate you have to actually get the layer you want. One layer will have alkaloids, one layer will have resins. Freezing it helps it separate also. And there is a chemistry tool known as a "Separatory Funnel" that is good for this.
In Perfuming there are 3 options. Enflourage, Concrete and Absolute.
Enflourage is plant material extracted in to a fat or oil. Ex: Coconut Oil, Butter, Vegetable Oil, Olive Oil, etc.
Concrete is an extraction that is dried. Ex: You could make strong dark Tea with a plant, then evaporate the water by boiling it all away, and you would have concrete of that plant. You could also let a plant sit in Alcohol or another Solvent, then filter out the plant material. Then let the solvent evaporate. Then you have Concrete also. Dry sifting also makes a form of Concrete.
Concrete can be used as Incense.
Absolute is a more pure extract. To get absolute you can do a few different things. The most common is distillation. This is the same way people make Moonshine. You make a dark tea with the plant, then put it in a Still and evaporate it to the other side. Any steam extraction method with get you Absolute. The Chemistry way to make Absolute is to do an extraction in a non-Polar Solvent, then do a wash with a Polar solvent. Or Polarization, Winterization and Filtration.
This will create a produce Perfume grade stuff.
If you are going to make a Perfume, usually you would get something called "Perfumer's Alcohol" and you would mix your Absolute with that, and other things like Lemonene or whatever Terpene you want in there.
In the Perfume industry they use the Molecule "Caryophyllene" to make Marijuana perfumes. I am pretty sure you could make something that smelled like Marijuana if you make Absolute from Patchouli and Uziza.