If it's a plain old field and not some club's flying field or somebody's private property, all you need is common sense and safety and to be aware of the basic FAA(or equivalent) regulations, that is...stay under 400 feet and you are good. This gets me thinking a bit though, as I have pretty blah spatial awareness so I really don't know what that looks like. I'm pretty sure I haven't exceeded it though.
Posting my response to @Gold Max for others in Canada or wanting to fly in Canada. I didn't realize his age. He is under 19. A basic pilot certificate can be obtained from Transport Canada at age 14. An advanced certificate at 16. Not sure how MAAC addresses junior members. Cost for them is $10 or $21 with the magazine.
For Americans flying in Canada and vice versa, AMA and MAAC have a reciprocity agreement that appears to cover members of each organization in the other's country. If you have membership in the association in your country, you can join the association in the other country if you choose but it isn't required. Link to reciprocity agreement below.
Two things can make you legal to fly in Canada right now.
First is completing the RPAS online Exam for Basic Pilot Certification and attaining a drone pilot certificate. Then each plane is supposed to be registered with Transport Canada at a cost of 5 bucks. Must have your pilot certificate number and plane registration number on each plane. Exam is 10 bucks a crack and you can repeat in 24 hours if you fail. Can do that over and over. Must recertify every two years.
Second is to join MAAC. Model Aeronautic Association of Canada. MAAC negotiated and exemption from the new RPAS regulations for its members. No need to pass the exam or register each plane. You must have your MAAC member number and the MAAC 1-800 number on each plane. Joining MAAC is $80 a year. I joined so I could fly at the local fields. Never dreamed this would be a benefit. Plus you get some liability insurance. Catch is you have to follow all MAAC Safety Procedures and Transport Canada regulations as you would with an RPAS pilot certificate.
I'm flying under my MAAC membership at the moment but plan to take the exam for basic. I still need to print out the MAAC safety procedures and exemption to have on hand with my membership proof should anyone come looking.