Should I spend time talking to 100+ potential customers before building, or just consult the handful I already work with?

It's highly unlikely that you will be able to find competent full-stack mobile developers willing to work with you for equity, but if you do, "fair" compensation would be 50% or more of the equity in the Company. Approaching any developer with just an idea, diminishes your credibility as a potential co-founder. Here's why: If you're non-technical, you must show a "relentless resourcefulness" in moving your idea forward. This means finding the money necessary to get an MVP or even click-able prototype completed to show that while you might not be technical, you have the ability to raise money, and have enough product sense that you can articulate that into a prototype. If you can't raise or spend the relatively small amount of money required to successfully build a prototype, what evidence are you providing that developer that you are going to be able to create value for the business long-term? Full-stack mobile developers (although this is often quite a misnomer) are one of the most in-demand skill-sets of all Silicon Valley companies. That means that you're competing against established companies that can pay top dollar, and still provide meaningful equity incentives as well as recently funded startups who have further along the road in turning their idea into reality. I would suggest that you look at hiring contractors (I know of some great mobile dev shops that are reasonable) to build your first version. Expect to go solo at least until you have some form of early prototype. Then, you're in a much better position to attract a technical co-founder. Happy to talk you through any of this at any point.

Whoa, start by reading the Lean book again; you're questions suggest you are making a classical mistake made by too many entrepreneurs who live and breath Lean Startup. An MVP is not the least you can show someone to evaluate whether or not building it is a good idea; an MVP is, by it's very definition, the Minimum Viable Product - not less than that. What is the minimum viable version of a professional collaboration network in which users create a professional profile visible to others? A website on which users can register, have a profile, and in some way collaborate with others: via QA, chat, content, etc. No? A minimum viable product is used not to validate if something is a good idea but that you can make it work; that you can acquire users through the means you think viable, you can monetize the business, and that you can learn from the users' experience and optimize that experience by improving the MVP. Now, that doesn't mean you just go build your MVP. I get the point of your question, but we should distinguish where you're at in the business and if you're ready for an MVP or you need to have more conversations with potential users. Worth noting, MOST entrepreneurs are ready to go right to an MVP. It's a bit of a misleading convention to think that entrepreneurs don't have a clue about the industry in which they work and what customers want; that is to say, you shouldn't be an entrepreneur trying to create this professional collaboration network if you don't know the market, have done some homework, talked to peers and friends, have some experience, etc. and already know that people DO want such a thing. Presuming you've done that, what would you present to potential users BEFORE actually building the MVP? For what do you need nothing more than some slides? It's not a trick question, you should show potential users slides and validate that what you intend to build is the best it can be. I call it "coffee shop testing" - build a slide of the homepage and the main screen used by registered users; sit in a coffee shop, and buy coffee for anyone who will give you 15 minutes. Show them the two slides and listen; don't explain, ONLY ask.... - For what is this a website? - Would you sign up for it? Why? - Would you tell your friends? Why? - What would you pay for it? Don't explain ANYTHING. If you have to explain something, verbally, you aren't ready to build your MVP - potential customers don't get it. Keep working with that slide alone until you get enough people who say they will sign up and know, roughly, what people will pay. THEN build your MVP and introduce it first to friends, family, peers, etc. to get your earliest adopters. At some point you're going to explore investors. There is no "ready" as the reaction from investors will entirely depend on who you're talking to, why, how much you need, etc. If you want to talk to investors with only the slides as you need capital to build the MVP, your investors are going to be banks, grants, crowdfunding, incubators, and MAYBE angels (banks are investors?! of course they are, don't think that startups only get money from people with cash to give you for equity). Know that it's VERY hard to raise money at this stage; why would I invest in your idea when all you've done is validate that people probably want it - you haven't built anything. A bank will give you a loan to do that, not many investors will take the risk. Still, know not that your MVP is "ready" but that at THAT stage, you have certain sources of capital with which you could have a conversation. When you build the MVP, those choices change. Now that you have something, don't talk to a bank, but a grant might still be viable. Certainly: angels, crowdfunding, accelerators, and maybe even VCs become interested. The extent to which they are depends on the traction you have relative to THEIR expectations - VCs are likely to want some significant adoption or revenue whereas Angels should be excited for your early adoption and validation and interested in helping you scale.

Wow, lots of questions here. Let me try to hit them in order: "Should I get a job or find investors?" IF you have access to enough investor capital (not debt and not your savings) and you can get to MVP and still maintain ownership of a sizable majority of the business then do it. IF that means debt financing then only use the debt lines the cost of which can be carried by returns generated by the use of funds. I would prefer to offer a convertible note to prospective investors that can be easily extended throughout both friends and family and seed rounds (up to $2M to $3M) to get to proof in the market. If you can get to revenue and earnings fast enough then you can avoid equity dilution all together. IF you cannot secure that find of funding AND you cannot produce enough revenue from your business to deliver sufficient earnings for you to live on, then by all means, you should find a way to make the money you need and not burn all your savings or mortgage your home If that means short term contract work that's great. Particularly if you can find log term work that is relevant to the business you're building. If that means taking a job then do that. IF you do that, then yes, be transparent with your employer and let them know you're working on your own business also. Hope this helps....

Find apps that are B2B and go to the review sections. Specifically going to Google's play or Chrome store and look at reviews and follow them to Google+ to engage. I took that same angle for B2C app I was building last year. Check it out. http://blendah.com/post/37331434653/lean-startup-hack

Stop thinking you don't have the skills to do something. You can learn anything if you decide to, but assuming up front that you can't (forever) is dangerous. my2cents