I used these and it definitely helped me progress well. It's important to have good 2nd string players who can be substituted quickly https://www.fcmobileforum.com/mm-tactics
Caveat: As great FC sages who greyed on the game say, Take a break and Just Chill when u R loosing.. no tactic can save you. Some blame it on distance from servers, some on AI cheating but bottom line is you can't win. I raised tickets on loosing/winning streaks but no real solution comes out (Probably there isn't one). So use this forum to vent out and we can all share the pain n joy of loving a not so perfect game :)