Removing spent blossoms, is the easiest way to keep plants blooming. Annuals especially will benefit from a periodic dead blossom removal.
Often, sticky leaves is caused by Scale. Scale is an insect that sucks the juices out of plants. The sticky stuff that accumulates around the plant is from insect secretion. Take a look at the undersides of the leaves for tan, black or brown bumps. Control Scale by suffocating the insect. A safe horticultural oil will do the trick.
When placing plants in conversation spots or on tables be careful to make sure that plants are not too large, hindering the conversation.
The most common insects that attack plants indoors are mealy bugs, scale, and mites. Inspect the your plant's leaves regularly for these pests.