Increase Pricing Packages

I run a boutique digital marketing agency (in my 4th year) and have needed to increase my pricing for a long time. I have been super picky up to now to avoid difficult people (based on bad experiences). I know that’s a negative thought. I just don’t want to create more stress in my life.

I have a few questions. 1) How do I know what to charge for my packages? 2) Is it wise to charge everyone the same price for my services? 3) Should I raise the cost for my current clients who are not paying nearly enough?

Thank you!