Reactive Form Validation Best Practices

I am interested in form validation and user feedback, specifically client side – before I to a Meteor method. Having reactive messages is a huge plus.

This is this most promising lead I’ve found so far:

I’d like to keep this straight Meteor, without Autoform or Simple Schema.

What are the best practices in this space?

Packages you might be interested in:

Thanks. But the thing is, I want to do all this without packages.