Engadget
Want to speed up your MacBook? Do these things first

Restart the MacBook first, then examine storage in System Settings > General > Storage and delete or offload unnecessary files if space is low. Use Activity Monitor to identify CPU-heavy or memory-intensive apps, quit or limit them, and remove unneeded login items or background permissions. Finally, verify that the Battery Power Mode is set to Automatic (or High Power for demanding tasks) rather than Low Power, and install any pending software updates.