When a dwarf has "no scheduled orders" for a certain month, their priority is to individually train. If they are Active, will invid train more, job is less of a priority than if under the Inactive schedule , where the job is the priority.
Under either active, or inactive, if you assign a month to train, they will give demonstrations, watch demonstrations, or spar. Sparring usually occurs if they are close to the same skill levels, not just small squads. You really want a dwarf with good skills in each squad, to give demonstrations. It really helps.
To start your basic military base, embark with a dwarf with novice in shield, armor use,wrestling, and dodging. This will be the militia commander. Then designate a barracks, and assign all non miners, woodcutter, hunters, and the doctors to it. Under the inactive schedule, assign them to train 4 times a year, in months that you expect no caravans. As soon as you can, produce/trade for shields and some type of true armor, to equip them with, if only 1 piece.(If they are at least wearing 1 piece of armor, they will get the benefit of armor use.) Use the militia commander to train this squad in the basics. When non essential dwarves become decently trained, when a migrant arrives with weapon skills, assign them to his/her squad, and equip with cheap weapons.
During training months, they can refresh their military skills.
As soon as new migrants arrive,rotate them into the militia squad, making a new squad for the older members. Assign the oldy militia squad to train once a year, and if you are paranoid, assign them a new uniform with better(Multiple pieces of) armor, and weapons. This makes for a good emergency fighting force.
If you are in a biome with not so dangerous wildlife, give potential archers the hunting labor. Will give them experience, plus food on the table. When not needed anymore, assign them to a squad with a militia trainee. They will target practice, and while in a training month, the trainee will teach them dodging, armor use, shield use.
Your use of patrols is a splendid one. It will mess up ambushes, plus give them something to do.