Creating a floor template will save you so much time and headache. 
I’m using drywall shims & tape but you could also use strips of cardboard or plastic with hot glue. Outline around the edges as well as the toilet drain. 

Plan your layout so the toilet drain can be cut out of two tiles along a grout line vs smack dab in the middle of a tile for easy cutting on a saw

Use self leveling spacers to help eliminate any lips that can stub a toe. Check your tile size & notched trowel to make sure you are using the correct one (it says on the box!). Bigger tiles need a larger towel. Red thing is G-flex uncoupling membrane which helps protect against cracks, movement with settling, and waterproofing. SAVE this for your future tile projects!