The lighting information on nursery tags can be somewhat confusing. The simple answer is - is the sun hitting the plant without any impediement or not. Windows do count as impediment, so any plant kept indoors will always be receiving indirect light. This is because light diffuses - or bends and curves its direction - when it passes through a cloth, glass, water etc. Most houseplants belong to plant families that thrive in indirect light and lower humidity conditions - plants that in their native habitat would lay low to jungle floors where only indirect light would be possible to grab onto through a tree canopy for example. While most houseplants would actually prefer more a higher quantity of light than we can provide in a house windowsill, they are often pretty happy to grab light through the diffusion of a window. Most are not equipped to handle direct unimpeded sun and exposure can result in leaf burn. 

Water is life, and also the main reason plants are killed. Plant roots keep the plant hydrated, but they also require oxygen. If you water too frequently and don't allow air to touch the roots from time to time, the tissue will die and rot - often leading to fungal diseases that will move up the plant as it weakens resulting in its ultimate demise. If you find this happens to you - considering changing your watering habits. Bottom watering by placing the pot in a bowl of water rather then pouring from the top is often a good method to reduce pathogen growth. Although plants all differ in how wet they like their feet - allowing soil to dry between thorough soakings is usually best practice.

Plants need light to make the sugars they consume to survive and wihtout enough light, they won't have enough food. The best location for a plant simply comes down to two factors: light intesnity and duration of exposure. As the sun rises and sets East and West respectively, these directions have direct light exposure for half of each day. Some plants may find East and West facing windows either not enough time in the sun, or that the sun may be too harsh. North and South facing windows will yield a greater length of time with light exposure, but the intensity of the light will not be as strong as the sun is not in the direct path. Here in the Northern Hemisphere, South Facing windows are the prized real estate for our photosythetic friends as the north facing direction often yields too low an intensity. This does not mean nothing will grow in anything but a south facing window, but if you live in an apartment with only north facing the types of plants you can suscessfully grow may be limited. 

Plants need light to make the sugars they consume to survive and wihtout enough light, they won't have enough food. The best location for a plant simply comes down to two factors: light intesnity and duration of exposure. As the sun rises and sets East and West respectively, these directions have direct light exposure for half of each day. Some plants may find East and West facing windows either not enough time in the sun, or that the sun may be too harsh. North and South facing windows will yield a greater length of time with light exposure, but the intensity of the light will not be as strong as the sun is not in the direct path. Here in the Northern Hemisphere, South Facing windows are the prized real estate for our photosythetic friends as the north facing direction often yields too low an intensity. This does not mean nothing will grow in anything but a south facing window, but if you live in an apartment with only north facing the types of plants you can suscessfully grow may be limited.