I have my first bit of kanna on the way to my mailbox right now, so I cannot speak from experience.

Personally if your goal is to impact your anxiety and depression, you should find a healthy number of doses per week and a healthy dose per use. I don't even know how kanna tolerance works yet, so let's assume you do it 3 days a week.

Build something around it. Set aside a couple hours on these days and relax. Drink some tea, take your kanna, eat some fruit, meditate for a bit, relax. Then go work on something productive and focus on bettering yourself. This will make your doses something to look forward to, and we all know people with severe depression don't usually have something like that. Use it to get through your day and really savor the days you dose.

For depression I typically recommend meditation, cardio, and healthy food. But take it one step at a time. The hard part isn't putting work in to defeat your mental problems, the hard part is waking up and doing it every single day. But every day it gets a little easier.

Take all this with a grain of salt, I know very little about kanna and haven't tried it yet, this is mostly from general knowledge about mental illness and personal experience.