This may be the most important question you need to ask yourself when launching a marketing campaign. If you aren’t clear about the answer to “what do you want me to DO?” your campaign’s not ready for prime time.
You need to have ONE, CLEAR call to action. Not three, not five - one. The Paradox of Choice tells us that if people are presented with too many options, they end paralyzed and unable to choose anything. But you need to have that one call to action. Otherwise, you have no campaign, and why are you bugging people in the first place?
Another common campaign planning flaw: you need to know what the next action you want people to take AFTER that is.
You are planning that your campaign will be at least somewhat successful, right? So at least some of your targets will actually take your desired action. Which means in their busy lives, they've chosen to engage with you. They've hopped onto the first rung of the ladder of engagement (a concept derived, as far as I can tell, from a 1969 paper on citizen participation).
What's the next rung?
You can't wait until your campaign is underway to figure that out. Attention spans are short, and there's always someone waiting to snatch that slice of focus you've earned for your association, profession, industry, or cause away from you. If you don't have a logical next step for people to take, one that deepens their relationship with you and further engages them - but not too far, too fast (you don't want to jump straight from the first flirty text exchange to asking them to marry you) - they'll flit away to someone who does.