Moving from reactive to proactive has been the key skill I have had to coach for individuals to progress in their career.
Reactive activity: Activity driven by Emails and phone calls, demand from stakeholders including customers
Proactive: developing and overall strategy, steps to achieve and setting up cadence calls. Building stakeholder relationships, focus on the projects and only check emails once or twice a day.
If you are the most productive in the morning, dont check email, allocate time for a project where we are at our peak in terms of attention and focus.
If you have worked in a customer service role where you have been responsive and reactive and then move into sales, you will need to adjust to Proactive work from mainly reactive. To make this transition look at training, reading the below book and also getting a coach.
It takes time to change behaviours but this adjustment is well worth the effort.
https://gettingthingsdone.com This is a great book to really nail your productivity.
If you are starting out in your career, learn project management skills as this will be a core skill for the Proactive time management.