Mac improve performance?

Add the maximum RAM (16 GB), remove all Login Items, and maintain at least 10% available space on the HDD. Others will tell you to empty cache and erase history -- waste of time. Nothing more can be done. You will have to get one of those 30 GHz Zarconium processor Macs with 128 GB of RAM to do better.... Oh, wait. That will be in 2020. Can you wait?