A little back story - I'm always a huge fan of trying to get my teams to play in a similar way to a style I see in real life. In FM18 my biggest challenge is beating the away day blues, I've tried a number of ways but I'm yet to figure one out to grind out consistent results.
I could be entirely wrong on this, I don't research tactics or use workshop items myself so maybe one day in the future I'll add a new tactic when I crack the structured solid defensive 'Mourinho/Allardyce' approach of completely nullifying the opponent. BUT, because I haven't found that yet, my most effective way so far is to outscore opponents, enter, KLOPP (demonstrated by Everton).

HERE'S THE TACTICAL APPROACH

Fast, attacking football with a high press. This is very much based on the way we saw Liverpool play last season, particularly the approach when Coutinho was used as part of a midfield three.
You'll see the full backs aren't overly attacking because we need some form of control, however they do venture forward. The real magic is once the ball gets to your Mezzala's (Coutinho and Wijnaldum if you like) and further.

WHY THE TWO MEZZALA'S?

The idea is straight forward, as this is an attacking formation (although I recommend playing counter against similar and higher rated teams) what we have with the mezzala role is a player who is creative, joins in the attack and drifts wide. In front of the two mezzala's there is two Inside Forwards, so what you'll find when you see one of your midfield attacking duo in a wide area, is that the IF is more central alongside the actual ST. If I've lost you at this point, essentially what you have is a group of four players who are all in positions to score and assist and due to the speed of the attack, you more often than not, outweigh the opponent.

THE STRIKER

On my screenshots you'll see that my striker is deployed as a Complete Forward, Pinamonti sucks as a False 9 in my experience, but he will get you 20+ goals a season consistently playing as a CF.
The point is though, have a specialist CF or F9 and this formation will do wonders.

INSTRUCTIONS

Very typical of what you would expect from this kind of tactic - push higher up, mark tighter etc.. winning the ball back ASAP basically. I encourage wing play because when your full backs do venture forward you'll find them in a lot of space with high potential for assists.

One final note which I hope people understand, the way your team reacts to new formations is very much dependent on the style of football you're changing from. My team has seamlessly transformed into this formation because last year's formation was based on a more 'Sir Alex Ferguson' approach, i.e they were already used to fast attacking football. It can sometimes take up to a full season for a new tactic to settle. I say this because it's a consideration not enough people have (not to cover my back if it doesn't work for you, I know it works in the end - Just understand it may not be perfect after 5 games).

I have not tested this in a lesser team, bear in mind while the players I have may not look like the best, I started this season off the back of losing the title on ♥♥♥♥♥♥♥♥ goal difference.