Check if your plant is getting the right amount of water. You are not watering enough if the leaves are growing slowly, dropping when otherwise healthy, and developing brown edges or the lower leaves curl and yellow. You are watering too much if leaves of different sizes are dropping, soft brown spots appear on the leaves or the bottom of your pot is surrounded with water and smells moldy.
Make sure your plant is getting the right amount of light. If the leaves are spaced far apart on the stems, abnormally small or the lower leaves turn yellow and drop, your plant may not get enough light. Most plants need between 16 and 18 hours of sunlight per day. If you are trying to get a plant to produce blossoms, many from temperate climates will not do it until they get less than 12 hours of light per day. (Tropical plants will flower with any length of day.) Plants have a natural mechanism to protect themselves from too much light, but if you really overexpose your plant, the color of the leaves may fade where they get the most light or the leaves may develop yellowish spots. I suggest that if you want to get the flourish plants, you can buy led grow lights for your indoor plants, so that you won't need to worry about the plants will die without enough exposure of sunlight.
Check the air humidity and temperature. If the air is too dry or too cold, the plant won't grow and the tips of the leaves will start to turn brown. Flower buds may fall off before they bloom.
Check the soil. If it is pulling away from the sides of the pot, you haven't been watering enough. The plant will continue to suffer even with more water unless you use something to break up the soil. Avoid severing the roots while you do this.
Research the proper levels of water, light, humidity and temperature for your plant, if you're not sure which way to alter things. Plants are as varied as cacti that thrive in sandy soil with infrequent moisture and orchids that can thrive without soil and only in high humidity.
Use a watering bulb or globe, if you are having trouble giving your plant the right amount of water. Fill it with water as needed and insert into the soil. If your plant needs more light, consider adding an electrical one. If your plant gets sunlight, make sure it gets some sunlight each day before you turn on the plant light. LED grow lights work the best.
Fertilize or repot your plant if it still is not growing as much as you'd like. Plants need minerals in the soil to grow, flower and bear fruit and seeds. Your local plant store sells liquid fertilizers you can mix with the water you give your plant, and you may want to try this first. They also sell bags of potting soil, or you can make your own if you're sure it is not already depleted of minerals (as soil from a long-time garden may be), and it has some organic matter in it.