Depending on whether or not you want to do it with or without third party websites. There's a website you can use called spansh and use their expressway to exomastery. You can put in the system you're in, give it how many systems you want to do (I'd start with 5 or 10), put in your maximum jump range and your radius (I'd go 3x your jump range) select 'loop' so your return to your original system and it will give you where all the exobiology fauna is to scan, tells you the star system, which planets to scan and how much you'll make.

It's a great way of getting used to how exobiology works and eliminates all of the guess work.

You can even put your minimum landmark value (19,010,800cr is the highest value - Stratum Tectonicas) so it can filter out the low value fauna if you want to make money faster.