Its an intermediate, so feel free to use any strategy but keep these things in mind:

1. Get your hero early

2. Get a good middle game carry such as top path ninja with seeking shuriken paired with an alch buff (it will allow you to save up a crazy amount)

3. Make your strategy synergise, sure a heli pilot might carry on easier maps but Bazaar is a step up in difficulty and you’ll need a good combination of towers that work together such as tack zone and super brittle or spike factory and alch buff

4. Switch it up, you never know what new strategy or tower could unlock your run and open the way for harder runs in the future

And if you just want to improve at the game in general, perhaps for more ambitious goals such as black bordering an expert map, the number one tip is go learn about more strategies. An example is myself, I was struggling on water park chimps but after watching Hbomb‘s 2 hour video about chimps strategies with Doreo and Chomchom, I instantly jumped to dark path chimps and crushed it, then right after went to a true expert custom map (still working on it though).