Keigo for advanced learners?

So I’m at a conversational level and I’ve been talking casually to friends for the past 5 years. I never intended on using it for work, but an opportunity came up that requires Japanese and English fluency, and the pay is really good so I thought I wouldn’t want to pass up on it.

I’ve always talked in a casual manner, and the closest I could get to keigo is teineigo when talking to older or newly met friends.

I’d like to ask if you have any advice or resources to learn keigo in like 2 weeks 😂 I plan to read and write essays and business emails but I don’t have much resources when it comes to vocabulary and commonly used keigo words