Privacy-centered instant messaging.
The best way to make sure you have a secure conversation, is to use an app that has as high level of protection. But even with those who don't have, and you are just stuck with using them, you can get the security and privacy you need. But keep in mind that you are helping that way those people who want your personal information and messages to leak and be in control of them.
Whistle is one of the best and most secure apps out there. We use two types of message encryption and don't use nor require your personal information, but the best thing is that your messages are only yours and the people you send them to. They are saved nowhere else so that no one, except the ones who can get to your phone, can read them.
You can also just see not to use any of the services offered by companies that are part of the Fourteen eyes. That is a pact of Fourteen countries that collect and share intelligence of their citizens, disturbing isn't it? The second step is using VPNs that have more levels of security. One of the best ones would be AirVPN with 162 servers, but since they are in Italy, which is a Fourteen eye country, that is not a good idea. Cryptostorm is also good, they have 18 servers, a free trial and are not too expencive, so make sure to check them out. NordVPN is not pricy, as well, and has stunning 475 servers.
Use a browser that gives you an extra layer of protection and even anonymity, as Tor, but Firefox is also a good choice. Think about installing additional encrypting services, as CryptoCat and Chatsecure. But know that if you don't share anything via instant messaging, nothing can be taken as well.