Coconut is the one that is the easiest. The lazy method is to just use coconut water but this may make you catch a cold if you live in a cold country. Another method is to grate the pulp and then add some water and then boil it. this will form a very liquid oil that will make your hair poky and rough when it dries. Just wash it off in an hour and you will see the results. If stink is not an issue for you, you can add curry leaves and even some gooseberry/amla pulp to the mixture. Do remember that despite being colorless, coconut leaves stains on your clothes.
Another simple diy is with gooseberry/amla. Just buy some natural coconut oil and boil it with some gooseberry pulp. Strain out the pulp and apply the oil to your hair. Use gloves for both diy because this is absolutely organic and you may even start staining your hands!