Generally don't talk for more than 90 seconds straight. Pause and let your interviewer ask questions. Ask them directly - "Should I continue?"
Control your vocab. "THIS WAS DIFFICULT BECAUSE". Reinforce the difficulty and complexity that you faced, don't necessarily gloss over details. Numbers, Numbers, Numbers.
Think about alternatives to what you did (journey of discovery). Could you have merged tools together? Could you build a completely new tool? Could you use an off the shelf solution? Could you use an open-source project? Could you have changed documentation to not have to build something else? Think about how much time you spent to have a minimal solution.