Italki isn't an instant chat tool and people can appear online, even if they're not actively browsing italki. There could be a window open with italki on their browser. If they use the app and are logged in, they also might appear being online, even they're not.
- write a little introduction about yourself and what kind of exchange you're interested in, in your profile
- correct English notebook entries by speakers of your target language
- browse through the forum and see reply to requests from speakers of your target language, like this one:
Here are more tips on how to look for a language exchange partner: