On this site we came as partners to talk with our friends. If you have so much friends .... of course some of them will be not so interesting for you. Choose in list of your Italki frends "your best friend or friends" and talk with there people often and interesting of there live exmple.
When you to stop on standart question as "Hello! How are you? What are you doing now?" It's not pretty to continue our dialog. (I think so) But if you will be writing to some person about yourself and interesting about his life, soon you could ask to his very interesting qustions, and (many books tald this thing) all peple like to talk about themrselves. If you will be tactful person then peolle will be continued write to you after "hello".
1) Ask questions
2) Interesting their life
3) Don't "disperse". Choose 1-3 persone and talk with them a lot ))))
Best wishes!