Is your startup for the local market or the global market?
Having the right startup in the right market is incredibly important. Every market is unique in their own ways, and while 1 product might work in one doesn't mean it'll work in the other. Also, being in a local market means that your marketing strategy might be very different from being in a global market where the channels where you acquire your users might be very different.
This is a good time to consider whether you want to start with a local or a global or national market. While it sounds glorious to be targeting a global market, often times if your startup requires a lot of user created content, then it might make sense to start with local first, because the "denser" your community is (in terms of location), the easier it is for them to connect and relate. Going global will spread your content too thin, and while you could get a lot of information in total, at any given location, the content might be very diluted.
A way to look at this is that if your service requires user created content to have value, and users are location sensitive, then it's best to start locally. If your service does not require user created content, and can create value immediately, then you can consider launching globally or nationally, but you still need to focus on marketing to 1 specific demographics.
PS. This guide's marketing channels are mostly for the global market. If you are targeting a local market where the marketing channels are different, then you can use our suggestions as reference to find equivalent ones for your own market or location.