I handwash many of my knits, regardless on what's on the label. I live in an apartment complex with a communal laundry facility. Those washers are commercial issue and don't have delicate cycles. That's why.
As far as technique, lol, I have a mid size plastic basin that I put on top of my kitchen sink for this purpose. I don't like to use the tub or the bathroom sink, since I'm tall and they sit too low. I don't like to use the kitchen sink without the plastic basin either, as there might be oils from food etc, that might ruin my clothes. I don't soak because my OCD tendencies go haywire if I see a lot of the dye coming out of the garment, so I do a quick dunk, rub on armpits and collar, and rinse routine. I have - don't laugh- a spaghetti drainer I use for rinsing. I put the soapy garment inside, let the faucet run atop for a few secs and I'm done. I wring the item without twisting, since I don't like to leave a lot of water inside the garment to weight it down, when hanging, since I don't have space to lay things flat. I then lay on a clothing rack to dry. Most things dry overnight. You might have discovered 1001 OCD tendencies thru this explanation, lol.
As far as soap, I use Woolite dark and regular Woolite. Some people hate this brand or don't see the benefit, but I've been using it for years with good results.