Watch the Using Effects online guitar lesson by Angus Clark from Hard Rock Survival Guide: Lead
If you are here because you skipped some of the neck knowledge concepts that just preceded this, you get a pass so long as you promise to go back and shed your scales and arpeggios after you've had some fun playing with your effect pedals.
Get this straight, this lesson is not an excuse to go out and buy (or stong-arm your folks into buying) a bunch of effects pedals (or worse yet, boutique effects pedals). These are some basic tips on what effects can do for your sound should you choose to use them. Keep in mind that every effect you put in your signal chain degrades your guitar's signal to some degree, so don't overload. The sound of a guitar plugged directly into an amp is magical. It's all downhill after that.
First up is the wah wah pedal. I recommend this as everyone's first effect. Hours of fun can be had and you really should practice what all the possibilities are. I demonstrate four effects: Wah on attack, wah on the beat, the toe flutter wah, and the static position.
Second is the delay. I demonstrate three effects: slapback, for a classic Zeppelin-esque effect; a pronounced dotted eighth note that can be played off of rhythmically; and a more subdued dotted eighth note delay that gives ambience to a lead sound.
Third is modulation. There are limitless numbers of modulation-based effects out there, my weapon of choice is a phase shifter so that's what I'm demonstrating here. I think the most modulation effects I ever had on my pedal board was three, and they were Chorus, Tremolo, and Phase Shifter. But that was a pop gig. I still sometimes like putting the Tremolo pedal on there with the Phase Shifter because Trem is almost it's own thing. Chorus sounds really dated to me at this point so I don't use it much. Flanger, Rotating Speaker emulation, and Phase Shifter all sound very similar, but I favor the Phase Shifter. And remember, a Phaser is a weapon on Star Trek, a Phase Shifter is a guitar pedal. Generally they all create "whoosh whoosh whoosh" sound. I know that David Gilmour has three versions of the rotating speaker effect in his signal chain: actual rotating speakers, a Uni-Vibe, and an Electric Mistress Flanger. But he's David Gilmour.
Lastly, boost or overdrive. I'm leaving out fuzz in this course because it's such a 60's psychedelic sounding effect. Boost and overdrive are more the sound of hard rock. They put your guitar more right up in a person's face and give you some additional presence. A little is all you need. Keep in mind sometimes it's best to have your lead sound achievable just by rolling the volume knob on your guitar up to 10, and then your rhythm sound is back at 7-8, and your clean tone is at 3-4. But you need a really good amp for that to work. When using channel switching or a pedal, It's a bad idea to have your lead tone be any more than 2-4 db hotter than your regular sound. The sound guy will hate you and kill you in the mix.