Increasing Sprint velocity or team performance is not an Art, it is purely Math & Science. We can follow the below few steps to increase the same.

#1 Use INVEST principle wisely for the story selection.

#2 Try to make unplanned leaves into planned leave as much as possible.

#3 Plan & resolve all impediments well in advance.

#4 Use Automation as much as possible, which will reduce QA duration.

#5 Avoid or reduce unnecessary meetings with the whole team, only invite required members & release as soon as they complete their discussion. Keep meeting short & crisp.

#6 Arrange regular & need basis KT, Knowledge Transfer which will help to increase team knowledge on the domain.

#7 Before any implementation junior team members will review his implementation approach with the experienced team members (Lead, Architect).

#8 Refine the story very well with the team. Make sure they understand very well the requirement & its dependency.

#9 As a Scrum Master know the team member’s personal challenges, due to working from home it is very much necessary to avoid Power issues, Internet issues & other issues. Our small investment or proper planning will solve these kinds of unnecessary challenges.

Last but not least, to increase team Velocity, you must consider team capacity & sprint duration including holidays, and don’t put unnecessary pressure on to team to increase the same.