Exciting stuff! I see a few questions here:
1. When is the right time to look for seed funding?
2. How do I appropriately talk to angel investors about said funding?

As for the first question, consider what your goals are and whether this funding can help you achieve those goals. Hopefully, one of those goals is to step out of your full time job and concentrate on this project full-time. It's perfectly acceptable to be doing this on the side, however, you'll find it VERY difficult to get any sort of funding unless your plan is to "quit your day job" the minute you accept your first bit of funding.

If you think some amount of seed funding will help you accomplish your goals short term (perhaps getting to prove out product-market-fit and position yourself to scale), then I would say that you're ready to begin talking to investors when you're able to articulate what your business is, your plan for getting to product-market-fit, AND you can visually show them something. Whether this is your MVP or a visual demo of some sort -- be at a point where you can *show* them your product.

In terms of how to position yourself to potential angel investors:

I'd specifically seek out people in your area that have something to add aside from just money. Angel investors invest money, yes -- but they also invest their time, knowledge, and connections. At this stage, you need this just as much as the money (whether you realize it or not). Position the meeting as "getting feedback." Meet with as many people that fit this mold as possible. You'll start to get a sense -- very quickly -- for who is a real potential angel investor for you, and who is not.

I'm happy to talk things through with you more, if needed. I hope that some of this helps...