To tune your car you will need some specialized hardware and software. Here are the steps you should take:
Diagnosis and understanding of the current condition.
ECU tuning equipment
Software
Setting up and commissioning
You can also download the necessary programs yourself https://89663-toyota.com/data-id-list/ Techstream (for automatic editing/modification of files) and Toylex (for diagnostics and coding of cars).
Please note that ECU tuning can affect the reliability and longevity of your engine, so be careful.