I am a lefty and have had very few problems at all. I do have shears for lefties. Sometimes reading directions/ instructions get me backwards. I just have to remember to cut from the right not the left... I have books from Eleanor burns and her graphics are great, but If I mimic her graphics it's for a righty. I have to remind myself to switch.
When I'm teaching my Mom something and she grabs my Olfa ergo trimmer and it's backwards for her (the blade moves left or right).
Someone mentioned Missouri Star you tubes... Other lefty quilters are Leah Day and Amy Gibson (she has a GREAT free block of the month at craftsy.com).