First of all, there might be legal restrictions depending on the country you're planning to run the ICO in.
Basically, you design your product first, which in your case means preparing - at the very minimum - a whitepaper in which you explain the use case of your system, how it benefits the people involved, what the raised funds will be used for, what your 5-year outlook looks like etc. The key to this is transparency and legitimacy, as you want to build trust in your product and don't want to be taken as a scam. Furthermore, a lot of marketing will be involved by running a website which explains your idea and a lot of social media involvement, getting people to discuss your ICO. Next, you'd have to provide an online tool on your site for the actual token sale or outsource it completely to a platform that provides ICO services.
If you provide me with further information, I'd be glad to analyze your situation in a call.
The following is not exhaustive nor is it legal advise.
1. You'll want to have a good 'crypto-economy' and plan for your token. What are the pressure mechanisms on price/supply. What is the actual use of the token within your application or network? Can your token just be substituted for ethereum or is your token unique and absolutely necessary for a new ERC-20 token.
2. Plan a legal structure.
The legal structure you choose is very important because it determines (to some extent) the governing law. Each token is different and therefore you should not just copy another but rather get a specific plan and structure for your token. The legal structure will likely impact your disclosure documents, KYC requirements, tax and ongoing legal requirements.
3. Pick Attorney(s) to draft legal agreements.
There are many agreements that need to be drafted including the purchase/sale/terms/disclosure agreements. It's best to have a law firm do these, and be covered by their professional liability insurance (if you can)!
4. Do KYC for your sale
Any token sale needs to abide by AML/CTF laws. This is an absolute must, and even if all else is equal, if you are found to be aiding or abetting terrorists or money launderers, you may find the long arm of the law reaching out for you. Your KYC should be connected to your ERC-20 contract. The folks at https://KYC-Chain.com may be able to help.
5. Be honest
Consumer protection laws exist for a reason, and you should have an ACTUAL product and use case.
**This is not tax or legal advise.
I've written more on this here: https://flagtheory.com/successful-initial-coin-offering/
At this time, the main tool to reach backers for your ICO are the whitepaper and the discussion platforms to answer questions that arise from potential backers. These two aspects have been disconnected, usually with a PDF version of the whitepaper and a comment board on a discussion site, but Mattervest is changing that model. The Mattervest site hosts interactive whitepapers, where users can comment and ask questions on each section of the document right inside of the whitepaper. Check it out at http://mattervest.com/evermarkets and http://mattervest.com/digipulse