Farrell made seven appearances on his maiden tour for the Lions this summer, including replacing Jonny Sexton in the decisive final Test against the Qantas Wallabies.
And he has been involved in all of Sarries' Premiership games so far this season with Mark McCall's men having a 100 per cent record.
The 22-year-old says he is relishing playing in an attack-minded side, and feels the experience of being Down Under with the Lions has improved his own game.
"I learnt a lot with the Lions - not just on the field but also off the field - particularly the way players prepared for games," he told The Telegraph.
"Watching idols of everyone's in the Lions shirts who had been at the top for a long, long time and watching how they prepared and the amount of work that goes in has been a massive factor in my learning.
"Not that I didn't prepare before, but just how much more I can do and start to do."
Saracens' try-scoring rate has doubled, and Farrell admits he is enjoying his club rugby.
"This year we are playing a bit more "same way" and playing a bit tighter to the rucks so we are a bit more of a threat off nine and 10," said Farrell.
"It is good in terms of options and I think we are thriving off it, especially the pack that we have got going forward and allowing some space for the backs."