Using filters and live effects we can creates lots of special effects instantly. You can smooth out sharp corners, create warp text, add drop shadows and make textures with the live effects. There are many filters in Illustrator and you can have lots of creativity in experimenting all the filters.
To create special effects, we can use either use Live Effects of Filters. Most of the time I will be using live effects as I can continue making changes using the Appearance Palette. The choice is up to you.
Live Effects: When you apply live effects to objects you can still continue to modify the effects and objects. You will need to expand the object break it into paths again.
Filters: When you apply filters, you can’t make changes to the effect anymore. It is already expanded.
There are some effects that uses raster effects instead of vector. This includes all of the effects in the bottom section of the Effect menu, and the Drop Shadow, Inner Glow, Outer Glow. When you apply raster effects, it uses the resolution in your raster settings which you can set it under Effect>Document Raster Effects Settings. Raster Effects are not considered as vector as it contains high resolution bitmap.
Round Corners (Effect>Stylize>Round Corners)
Round Corners is very useful in making smooth corners from sharp angles. You can set the Radius to adjust the amount of smoothness you need for the corners. It can add style to your icons and making your illustrations appear more natural.
This is one of my favourite filter. It can make you text stand out from the crowd by distorting it using arc, fisheye and wave effects. It can also bend bend boring lines to curves. Something to spend time experimenting with.
Roughen, Zig Zag and Twist are some handy tools under Distort to quickly make wave or roughening the edges. You can make make paper tears, waves and terrains with it. Below is an example how I can make a mountain skyline just by roughening a line.
After you have applied Live Effects, you can edit it with your Appearance Palette. Below shows the arrow with Round Corners effect. You can edit it by double clicking on the effect or delete it by clicking on the dustbin icon..
There are many more things you can do with live effects, so spend some time an experiment with it. Remember to go Object>Expand Appearance if you need to expand the shapes.