Smoke off the arch way in B site that leads to banana and set up a cross fire. Your mid player should be able to give you a warning that they are coming Squeaky ahead of time and can also provide early back up. You can easily hear Ts in Banana if you play near the stairs that lead to Squeaky.

As for A Site you should have a sniper play outside, preferably with an AWP. The 2nd A Player can play Upper and drop down to support outside if needed. The Mid player can take over Upper during this. The Upper A player can easily hear an A Ramp push unless they walk it.

Good audio / headphones are very important for your Mid / Upper A players. There's a ton of info to be gained by just listening.