Layer if necessary. If it is cold to start out, make sure that you wear shorts under your sweatpants so that you can take them off if you get too hot. You can also wear a t-shirt underneath your long-sleeve or sweatshirt for the same purpose.
Turf shoes are acceptable only when on playing on turf. Cleats cannot have metal spikes, front toe spikes, or anything that may hurt another player.
This makes it easier to see in the game. You can use skinny and soft headbands to hold your hair from falling in your face.
Jackets and warm-up shirts cannot be worn over your team shirt because it hides what team you are on, and is considered cheating. Zipper-less jackets, sweatshirts (with hood down) can be worn under your shirt. All types and colours of under shirts are considered acceptable as long as it is worn under your shirt.
Leggings to go under your shorts are acceptable. Goalies are allowed to wear pants.
This is particularly encouraged if you have braces or any other condition with your teeth. Gel ones are great.
You are going to need a good pair of gloves. Wear a different color shirt.