Where can I find people to communicate in Chinese to learn and improve it?
Depending on how easy it is for you to get in touch with native speakers IRL, I suggest the following:

1) natives everywhere:

download Wechat 微信 and use the "People near me" function (附近的人), it will show people in a 5-10km radius near you that are online right now. Given that Chinese people do tend to use Wechat more often than non-Chinese, your chances to meet people will increase. You could start chatting people up randomly or based on mutual interests, and even hang out together. 

However, don't expect natives to be willing to speak in Chinese to you ALL the time. Keep in mind that people speak their native language naturally, which means they will quickly become frustrated if they have to put too much effort in communicating with you. The worse is your Chinese, the sooner they'll feel like switching to a language they can have an actual conversation with you with.
In order to mitigate this outcome, you either improve your level BEFOREHAND or you specifically look for someone interested in language exchange.

2) I just have an internet connection:

speaking about language exchange, that's exactly what you want to go for if there are no natives able to physically go out with you.
I can recommend LingQ, lang-8, HelloTalk (app) or the excellent italki  where you can connect with real people that will correct your sentences and answer your questions (provided you do the same for them).