Not all cosplayers attend a lot of conventions because some just huge anime fans and they enjoy dressing up like their favorite character. Sometimes those cosplyers tempt to go to random places in costume for non-photo days, but it is very boring because nobody can see your amazing costume. Do you think it is a good idea to cosplay outside of conventon? Can you cosplay when a convention is not going on?
If you can not wait for a convention, you can run cosplay or photoshoot events between cons and you can exchange your costume as well as make friends with other cosplayers. But you should remember that if you go public in costume, people will look at you funny and give you some unhappy looks, you maybe interrupted and even offended because seeing costumes is a very odd thing outside of events and stage shows. So you have to be more careful choose your cosplay location. Those places such as stores and malls you should avoid.
The best safe and simple way to cosplay outside of convention is to go to these situations where you seem you unintentionally cosplay outside of a convention such as going outside of the convention area to eat, using public transportation to and from a con, pick up a last minute thing from a store, etc.