I do a lot of ground work and flexing/give exercises on the ground. I usually will "bit" one up in a halter tied to either a surcingle or a saddle.
I usually start driving them during this period too. I start in a halter then will introduce a snaffle and bit them up in it. Then I will drive in the snaffle. Age is the factor on when I will actually begin riding them.
I like bitting them up so that they learn to give to pressure, immediately reward themselves with release of pressure and they only fight themselves. We are human and tend to not always be consistent with our give and take - especially on the young guys. There is only one right when they are bitted.
Story: Now my 3 yr old filly has been handled nearly daily since I imprinted her at birth. That cow pulled a high O silver the other day. I put her in a cowboy snaffle for the 3rd time. She started pulling the reins from me and locking up while I was riding, so I got off and went to back her and she flipped all the way over. I bitted her up for 30 min. Each side and she has been sweet as pie since. Glad I felt the need to get off, cause she was probably ready to do that with the slightest inclination. She has never done anything that extreme before, though she will pin her ears and kick out when I get to working her hard and asking for a lot of collection.
Told her today I was going to send her to a cowboy trainer I know who would work her like I have never thought of working her. My training regime will be a walk in the park compared to what he will put her through. She really starts acting like a beach, I will put a barrel pattern on her. She'll be begging to go back to WP.
Sorry for the vent