I joined Mages guilde so which guilde should I choose next?

Brotherhood, Thieves, Fighters?

I want most benefit and 0 INFAMY.

Well, the Dark Brotherhood isn't normally associated with rainbows and cute cuddly guars. Since they are kind of sort of assassins, chances are good you aren't going to get Fame from doing the contracts they give out. Thieves tend to steal things and that generally doesn't make people, especially the people whose stuff was stolen, happy about it. Again, Fame usually isn't the result. Fighter's guild doesn't have a bad reputation.

There's no order, man. Just do whatever interests you the most. For better or worse, you can be a member of all guilds simultaneously, so there's no reason to stress.

Err, yeah. This being the General forum and not the spoiler forum, if you're looking to avoid infamy then Fighters Guild is the one you want out of the three. There's also usually a way to get rid of infamy too if you're concerned about it.

If you have KOTN DLC, then I would have done DB and Thieves guild questline first, then Fighters guild and Mages guild questline, and after that first quest of KOTN - Pilgrimage that will get you rid of infamy.