The startup will be in travel technology space. Need to come up with a plan on how to get initial subscribers (its a paid service). I am talking about 5-10k per month.
Would like to know what else can we do aside from the usual advice of blogging, SEO, PPC, Ads and mass email.
Without knowing more (idea, price point, audience, b2b or b2c etc.), it is hard to give you in-depth or potentially relevant advice. Would say, initial thought is that your target for your subscribers is fairly punchy and would need some considerable investment from both a perforce marketing perspective but also wider activity.
There are things that can be done to optimise your current activity e.g. your PPC conversion. For example, if you're a new company and there is limited info about you in the public domain it may be harder for you to convert a click to a subscriber as there may be lack of trust. Would you give money to a new company if you didn't know if what they were selling was any good or not? So things like reviews and endorsements from experts, media, bloggers, journalists in the sector are important.
Areas to look at would be:
PR - engaging the industry with your idea or product. Be that trade media or consumer depending on the audeince
Influencer outreach - hitting up the influential people in that industry and getting them onboard so they talk about you socially, on blogs, twitter etc.
Community engagement - working with existing online communities that are in your niche/sector and getting key people there to talk about it and test your product out
Social media - activating your current customer base through engaging content so they share with their followers (friends have friends that are in similar sectors) and also showing customers they have somewhere public to come should things not go to plan
Hope this helps, would need to know more to help further. Give me a shout if you want to talk. Cheers.