When your product is first launched being marketed and take up is no good (inevitably so), how do you deduce that it's a result of...
Given that marketing effort is actively being done in a variety of channels and yet haven't got enough acquisition, it may mean that either (1) the awareness campaign is not effective, or (2) the product is just attractive enough. Or it could be both.
What metric do you use to reliably tell which factor is the culprit?
I think your problem is relying on AARRR before they apply.
If the usefulness and excitement of the product itself is still in question, then it's not time to pour on the gas and get your pipeline doing. Rather, you're still in "finding product/market fit" stage, not in "found it, now get the word out and optimize" stage.
Think about it this way: If you don't know if the product is right or what kind of person wants it or why, marketing dollars are almost surely wasted.
Instead of looking at meager "metrics," I would get out and physically talk to your potential customers, show them what you have, get their feedback in person, etc., until you get to the point where your demos are blowing people away and they can't wait to try it.
Then you'll know your product is desirable, then it's (relatively) easy to get started with the right ad channels with the right ad message, and then your metrics make sense, and iteration is clear too.
do you have any customer / target market to do some validation against?
Have you defined what you believe is your minimum viable product and do some confirmation testing?
Can you reach out to any of these people and ask them directly about your product?
Do you have a feedback page / service that allows people to post their views? (getsatisfaction offers a pretty good service... and they didn't start out to build what they offer now!)
Bottom line: best way to determine the next move is to look outside your walls and validate your ideas with your target market. If your current base of respondents isn't big enough, then target "where they live" and run campaigns (adsense, contests, etc.) to gain a statistically valid number of members and ask them.
I know, its not always as easy as it sounds... but good luck!
Is this some social app or is it something that can benefit an individual?
If you started off with a "If you build it they will come." marketing plan (None) then you can't rule out a lack of awareness. Or do you consider a lack of awareness as, they've seen your site/app but they don't get the purpose/benefit/etc.?
What does it take for your app to be remarkable? I think Evernote is remarkable for 4 reasons:
Sharing is not that big of a deal for me, since I use it for personal notes that no one cares about, so as long as enough people use it to keep it free, I don't care if my friends or family use it like Facebook (What's the point of uploading my photos if everyone just wants me to email them a copy?).
Have you posted anything here, so we can check it out?
Building and launching a product is, perhaps, 40% of what you need to do to run a sucessful software company. (One that sells products or services and makes money.) The other 60% includes things like marketing, advertsing, promoting and much more. The question is, did you only do the first 40% and skip the last 60%?
To put it another way- people, for the most part, are not just going to discover your product and then buy it. You have to lead them by the nose to your product, convince them it is the solution to their problem, and the step them trough the process of buying it. Are you doing that?
And if you think that adverting and marketing aren't important, consider this. Back in the early 90's computer memory was at a premium. A company named Syncronys Software sold over 700,000 copies of a product called SoftRAM. The product claimed to double your system's RAM by compressing and decompressing system memory on the fly. The problem was it not only didn't do anything of the sort- it actually slowed your computer down. After years of sales people began to complain and the FTC started to investigate. Syncronys Software did a study that showed 82% of all its users were satisfied with the software. Eventually German hackers decompiled the code and demonstrated that it did nothing. The point of this story is that a company sold over 700,000 copies of a program (in the 90's) that did nothing, all through the power of marketing.