Original Post — Direct link
I have a hard time figuring out what you have to do to gain the different trophies.

Here is what I have found out so far, maybe you can join in and give further information:
EDIT: Updated with replies.


Completing Summer campaign with all author medals (7 trophies)


Completing Summer campaign with all gold medals
Completing a tier (same colour) of 5 tracks on Summer campaign with all author medals
Getting 7 author medals on TOTD "in a complete week"


Completing a tier (same colour) of 5 tracks on Summer campaign with all gold medals
Getting 10 author medals in user made campaign (only once per campaign)
Getting 7 gold medals on TOTD "in a complete week"


Online Race - finishing in the top x (depending on the number of players - populated lobby)
Getting 10 golds in user made campaign (only once per campaign)


Online Race - finishing in the top x (depending on the number of players)
over 4 years ago - softyBcKK - Direct link
Hello!

First, it's really interesting seeing you discover the various challenges to win trophies

I've seen many messages about TOTD and how trophies are given there, basically, you have 2 ways to win trophies with TOTD, the first one you found is getting 7 gold or author medals on a complete week.
The second one is based on daily ranking on the TOTD, but as we experienced some issues concerning the rankings since the release, some of the trophies were not sent to players. We will give you an update on that once everything is fixed.

On a global note, we currently do not plan to release an exact explanation of which trophies you can get through which challenge as we are still making some changes. But you've found most of the challenges!

National (Silver) ranks should also be available pretty soon which will change the type of trophies you'll be able to win in multiplayer. We've also worked on a different algorithm so that everyone gets a trophy after a Time Attack.

Thanks!