room simulations are fun and you can start testing this way without spending a lot of money
https://plugins4free.com/plugin/3772/
https://plugins4free.com/plugin/2465/
mixing with headphones can introduce some manageable problems, but the room simulations really help with something very important that you miss when using headphones: the crossfadefeed
Edit: now i've realised that the right word is crossFEED lol