....don't worry about the nit picky comments, some people rather than answer your question would rather try to be-little you.
If you are just starting out then I would recommend you get a copy of Robert Bucknells book 'Foxing with Lamp & Rifle' it is very informative and you will find it very useful and you can easily re-sell it and get some money back afterwards.
If by 'best' you mean 'easiest' then in my opinion it would be this time of year when this years cubs are easily lamped and called in. Also as soon as any crop field has been harvested the foxes will be there that night