Hi Kristen,
Great questions - and you're lucky, their are LOTS of options for adding data about your leads without the need for a form. This in-database enrichment is supplied by vendors like InsideView, NetProspex, ReachForce, Social123, Builtwith, Datanyze and many others. In some cases it's as simple as connecting the software to your Marketo or Salesforce instance, turning it on, and poof! lots of additional data. It really depends on what your market place looks like and how you would use the data as to who is the best fit. If you don't have a plan for how you'll use it, it's just a bunch of clutter. The are also solutions to add this extra info as folks fill out your lead form.
As for what's the ideal place to insert a lead form, there's an element of trial and error, but generally you want to 'ungate" (no form) as much content as possible so prospects can find everything they need if they are considering working with you, but add a lead form to super interesting content assets like "ultimate guide to negotiating [in your industry]" or "2015 Survey on [stuff really compelling in your industry].
- Mary Firme