I'm developing an RTS game and I want to add multiplayer support to my game.

I picked the easiest technique to implement for start frame locking technique.

1. I used server client networking architecture (I think it's my first mistake I think using peer to peer is a better one for this)
2. On game update every clients send their commands and maybe receive some command then render the frame and wait for all clients to send their update complete message then all of them can go for the next frame.

I send commands and all logic is calculated on the clients based on commands but the clients can go out of sync easily. Every AI controlled units make different decisions on each clients

What I have to do to sync my game? Do you suggest me a better network architecture or technique?