Working with forms in Meteor, using selectors for every input
As far as I know, Meteor's reactivity is one-way: changes in data are reflected in the DOM. To go the other way (DOM to data) there's two common methods: 1) grabbing data directly from the DOM when it's needed (i.e. to save it) as you've done above and 2) binding DOM elements to data models, and using the data models for CRUD operations.

1 is simpler to implement, but 2 gives you more control over data-flow, subscriptions, and life-cycles. 2 has plenty of great libraries you can use, so you don't have to reinvent the wheel just to leverage these benefits. Backbone.js is probably the most well known plain-JavaScript library for this sort of thing (also check out Lo-Dash and Exoskeleton if you haven't), but the Meteor ecosystem may have a preferred library for this.