The Ultimate stillwater chub method, provided they haven't gone predatory, is spraying maggots with the waggler as has been mentioned;
Asa general rule, try and fish with the wind behind you and fish out as far as you can fire the maggots, but always cast past the free offerings and draw the float back in to the feed.
Feed little and often, roughly every 20-30 seconds, this will change depending on the conditions on the day, but it's a good starting point. If you have the patience try feeding for 30-60 minutes before you cast in...
Start with the float set at mid-depth, if no bites or line bites are forthcoming within about 20-30 minutes then deepen off until you start getting bites of some sort.
When they're really 'having it' you can get the chub swirling right on the surface with this method.
Fish 2lb-2.6lb hook lengths to a size 22 or 20 hook and single maggot, using a waggler heavy enough to cast past your feed and don't put any shot below the float, use a micro swivel to connect your hooklength to the main line, that's all that's needed. Try and use a hooklength roughly half the depth you are fishing too.
There are a multitude of other little tricks and tips with this method, but these are the basics and should get you catching fish, this method has brought me hundreds of stillwater chub over the years to almost 8lb's, so enjoy and good luck, it can be hard work, but very rewarding.
Oh one more tip, buy plenty of catapult spares, you'll know you're doing it right when you keep having to replace snapped elastic or torn cups...../forum/smilies/wink_smiley.gif