how to beat the hard levels with no booster

Hello @domo123 and welcome to Soda community!

It depends on the level, we might need to replay a level a lot to find a strategy and/or get a lucky board. Which level are you stuck with?

Usually I wait for double delish fish booster given by daily bonus which doubles all fish and creates more blockers destruction. Sometimes starting to play around midnight, waiting for midnight and claiming next day daily bonus too might help as I get 2 types of timed boosters for free this way.

I recommend playing Shipmates if it's available in your game. We can earn boosters without playing any level which is great when we're stuck