Without any authority or credentials in this space you are going to face a very rough time with sales. The kind of startup willing to hire a random "general startup consultant" without a proven track record is also the kind that will fail and leave you with an even worse reputation.
You should focus on a single area or niche that you can do very well and has direct monetary value to a startup. What that area or set of skills turns out to be is for you to decide. It is better to be loved by a handful of people than try to be "maybe helpful" to every startup.
Personally I have been getting into the business of Pre-Launches for startups and programmers who are still working on finishing their MVP's. These programmers don't want to spend dozens or hundreds of hours learning about cheaply finding their customers online, building landing pages that convert, or growing their email list of future customers. They just want to be able to launch their product and acquire their first batch of users. Taking this headache away from them gives them the validation and encouragement they need to finish their MVPs and the time they saved by not building and marketing their pre-launch landing page can be used to instead finish their core functionality.
Thats just my 2 cents.
