To effectively plan influencer activations within integrated media plans, agencies typically follow these steps:

1. Defining Objectives: Initially, determine what you hope to achieve through influencer marketing. This could be increased brand awareness, boosted sales, or improved brand reputation.

2. Audience Identification: Next, define the target audience for the campaign. This could be based on demographics, online behaviour or interests.

3. Influencer Discovery: Tools like Flinque, Grin, or AspireIQ, are useful for finding the right influencers. They look at social metrics, audience engagement, past partnerships, and authenticity to ensure brand alignment.

4. Content Strategy Development: The agency and influencer collaborate to design content that will engage the intended audience and fulfill the campaign objectives.

5. Campaign Implementation: Launch the campaign across selected social media channels.

6. Tracking & Reporting: Use analytics tools to monitor campaign performance and adjust strategies if needed. Most platforms, including Flinque, offer real-time performance tracking and ROI measurement tools.

Please note, the tool or platform best suited to your specific needs will depend on a variety of factors such as size of campaign, budget, target audience, and more.

Flinque, for instance, offers a data-driven approach to influencer discovery and campaign management. Its features include audience analytics, performance tracking, and management of influencer relationships, which may be useful for brands and agencies aiming to streamline their influencer marketing workflows.

This approach allows agencies to create integrated media plans that leverage influencers in a strategic, planned, and measurable manner, thus effectively reaching and engaging target audiences, and maximizing ROI. Remember, every brand and campaign is unique, so plans should be tailored to fit individual brand goals and target audiences.