Plants care can generally be easy or complex depending upon the type of that plant , but the care key points are the same. There are few things that should be taken care of, lighting, watering, soil, humidity and fertilizing.

Light: Ofcourse plants require light for survival, but the amount of light required by different plants are different. Some need low light conditions, some require more light, some require filtered light and some can take few hours of direct sunlight.

Watering : You should be really careful while watering your plants. Excess watering can cause root rot and under watering can make the plant droopy. Yellow leaves, dried leaves can be because of under watering. If your plant still looks dull after watering it and has yellow leaves, it can be due to over watering.

Soil : A well draining soil is good for all the plants. It will reduce the chances of root rot.

Some plants like succulents and cactus requires dry soil for for such plants well draining soil is a must.

Humidity : There are some plants that prefer more humidity. They will grow in less humidity environment but will more humidity they will grow faster and healthier. Some plants prefer less humidity.

Fertilizing : Most indoor plants do not require much fertilizing. Fertilizing once a month will do or you can also fertilize little everytime when you water your plants.

Before buying plants always go through the care of that plant but also note that it won't be helpful always. Observe your plant and understand what it needs and care for it accordingly.