Gutterman thread, a good seam ripper, good scissors (I like Kai, but Fiskars are ok to start with) larger ones for fabric cutting and a smaller one for trimming threads at the machine.. Schmetz or organ needles in at least 2 different sizes ( size 11 or 70 for light weight fabric, size 14 or 80 for medium weights, or size 16 or 90 for heavier weight fabric) and be prepared to change the needles fairly often depending on your sewing times. Decent tape measure and rigid rulers are important, too.
Good long pins, or even better, the new clips which come in different sizes, prevent lots of finger sticks. i also like a magnetic dish if youre using pins to contain them. Chalk markers are safer than the ”eraseable“ markers which can be accidentally permanently set. a good pressing surface with a good steam iron and a good pressing cloth is also a must for turning out profesionally finished items. There's more, but it's a start.
Q