The most important part of learning ballet is having comfortable shoes.
If your shoes are the least bit uncomfortable or poorly fitting, then
you will have trouble dancing and learning moves. Even if they seem
comfortable, they might have some aspect that makes it more likely to
sustain injury to your feet. If you have feet that are usually hard to
fit in shoes (if they are especially wide or tall, for example) then you
may have trouble searching for the right ballet shoes. But no matter
what, you should be diligent until you find the perfect ones.
You should look at the particular shapes that your feet make. The
outline of your toes can range from an almost perfect square to very
rounded. Your shoes should fit the shape of your toes very well. Some
people have a 2nd toe that is longer than their 1st toe. This needs to
be accommodated, otherwise you will be uncomfortable in your shoes.
There are different things that can be used to modify shoes for
particular toes. These include separators, and fitting kits. You can
take a regular shoe, and modify it to fit your feet.