There are as many ways to curl hair as there are ways to do a smoky eye. While your basic tools are the same - curling iron, flat iron, or hair rollers - there are so many different techniques you can employ to create your desired look.
When it comes to conical hair rollers or curlers, you can create loose curls or tight ringlets depending on how - and from where - you wrap your hair. Check out this video for two different ways to curl your hair.
How to curl your hair with conical hair rollers/curlers. round/spiral curls/waves without heat