That is important, good advice. Here's some more:
Protective headgear is also essential. Bike, football or construction helmets (adorned with yer favourite anarchist stickers) will protect your head from pretty much any projectiles, as well as those pesky batons. Scuba goggles, ski goggles, or other crash-resistant eyeware is also pretty necessary. Swim goggles protect from gas and pepper spray ("oooohhh, debilitating" -H.S.) but not necessarily from a rubber bullet to to face. Big goggles do, at least moreso.
Wear layers. The thicker your clothing, the less likely you'll bleed internally. Layers of cardboard folded around foam padding (hospital eggshell foam mattresses are PERFECT) and duct-taped on under sweatshirts, while not bulletproof, definitely soften blows. They also make you appear larger, frightening your enemies. Check sporting-goods stores for shopliftable padding: shinguards, skating gear, and for the gentlemen, plastic cups. Think baseball catchers. And don't forget hockey: those guys (and gals) have helmets that come with protective face shields. The mouthguards boxers wear aren't a bad idea, either. Take notes from Ya Basta, the Stay-Puff giants of the protest world.
The best shields avaliable to the modern-day street fighting anarchist (or anyone else, for that matter) are littering every highway in amerika. Unless, of course, you can somehow convieve a way to knock over a Medieval Times. I'm sure you've all seen the bright-orange barrels used to block off lanes for construction. Snag a few the next time you see 'em. Cut the top off (the handle makes for a nice circular mini-shield) and then cut the barrel in half. Add some padding and straps for gripping on the inside, and presto, you've got two body-length riot shields. Paint 'em black and/or red for the menacing effect, or decorate 'em with your favorite care-bears if you're the nonviolent type. (Yeah, so I used to watch that show. It fomented my present-day anarchist tendencies. Didn't you know they were an anti-capitalist commune?)
Then, study Roman Army tactics (or just watch "Gladiator") regarding shield formation, locking shields, and the famous "tortoise" manuever. Practice shielding slingshot-wielding comrades, covering your collective rear, and the good old-fashioned Charge.
I'm sure most people who have found their way to this page, and had the gumption to open this picture, are pretty up on their street combat tactics, but hey, we can always use a refresher course. And you have to admit, the traffic-barrel idea is a pretty good one. Until next time, this is Emma G, reminding you to keep those slingshots swingin'.