One possibility is that the throttle plate has carbon around it preventing it from closing all the way. Remove the air intake hose from the throttle body. Using a cloth and some spray carburetor cleaner, clean the bore of the air intake around the throttle plate.
If it has a stick shift and clutch, it is standard. If no clutch and stick shift, it is an automatic.
Revving your engine past its shift points is never a good idea. Unless you are on a track day, revving your engine past its limits not only means consuming more gas, but your car starts revving heavily and if you continue to do so, you will damage your transfer case.
A stick shift with a clutch
you need a clutch that's all
Type of vehicle and is it a standard or automatic? Could be shifter linkage, clutch, something stuck around the shifter. If standard, will it shift into reverse when the engine is off? If so, it is most likely the clutch slave cylinder. Could be the master cylinder, but the slave usually goes bad first.
To not allow the engine to start unless the shift is in park or neutral in an automatic or the clutch is depressed in a standard transmission.
The clutch will be very loose and it will be hard to come out of any gear.
It disengages the engine from the driveshaft allowing you to shift the gears on your transmission.
You press the clutch, and shift gears. There are great instructional videos on youtube.
Shifting gears on a street bike depends on two things: your desired speed/mode of travel, and the engine revolutions, in RPM, of your machine. There is a point where the RPM meter shows such a low rev, that shifting gears at this point will stall the engine, stopping the motor. Shifting to first gear, which is the largest and most powerful gear in your engine, should be the easiest, starting off at about 1,500 to 2,500 RPM, while slowly releasing your clutch. Here's where the desired speed/mode of travel comes in: are you revving up for a fast ride, or are you just cruising slowly, taking in the sights? If you're on a race-track, or on a clear, safe, familiar highway, revving to a fast ride will mean accelerating to 8,500 RPM or more, before releasing the accelerator slightly, depressing your clutch lever, shifting to 2nd gear, and releasing clutch while revving up to 8,500 RPM or so, again to shift to 3rd. If you are cruising slowly, changing gears at 2,500 to 3,000 RPM should give you a steady, comfortable cruising shift without stalling your engine. Remember: the higher the gear you are shifting to, the higher your engine revolutions should be.
A manual (standard) transmission.
Not sure what you're asking about. I have a 1998 S10 standard shift that still has a clutch pedal.