Gerunds are a noun form of a verb that ends in -ing. They are oftern used when:
- As a subject.
 
Example
- Reading on tablets and phones isn’t very good for your eyes.
 - Travelling around the world has always been my dream.
 
- After a preposition.
 
Example
- I’m tired of waiting. Let’s go home.
 - I’m not very good at playing sports.
 - We are looking forward to seeing you soon. (to is a preposition.)
 
- After some verbs such as avoid, enjoy, finish, hate, keep, like, love, don’t mind, prefer, recommend, spend time, stop, suggest, etc.
 
Example
- I stopped playing football when I got married.
 - Have you finished painting the house?
 
Verbs that are followed by infinitives
Here are some verbs I frequently misuse, they should be followed by an infinitive instead of a gerund. Such as ask (someone), decide, forget, help, hope, learn, need, offer, plan, promise, remember, seem, try, want, would like, would love, would hate, would prefer, etc.
References