Here are some tips on how you can optimise your cold email campaigns and reply rates to improve your campaigns success in booking meeting:

Personalization: Make sure to personalize your emails with the recipient's name and other relevant information, such as their company or location. This can make your email stand out and increase the likelihood of it being opened and replied to.

Subject line: Your subject line is one of the most important parts of your email, as it's the first thing the recipient will see. Make sure your subject line is short, eye-catching and relevant to the recipient's interests.

Email Content: Keep your email short and to the point. Make sure to clearly state the purpose of your email, and avoid using overly salesy language or making false promises.

Follow-up: Don't be afraid to follow up with recipients who haven't replied to your initial email. A polite follow-up can help to increase your reply rates, especially if the recipient simply overlooked your initial email.

Segmentation: Segment your email list based on factors such as location, industry, or previous engagement with your brand. This will allow you to create more targeted, personalised email campaigns that are more likely to resonate with your audience.

Warm-up period: Gradually increase the number of emails you send during the warm-up period to avoid overwhelming your recipients and risking your emails being marked as spam.

Keep in mind that optimisation is an ongoing process, and you should continually analyse and adjust your strategy as needed to ensure your campaigns remain effective.