If you're using a multimeter for the first time, one of the things you'll need to learn is how to read it, which isn't that obvious. This article explains in detail how to read the current and voltage using the multiple scales on an analog multimeter or multitester (the kind with a pointer), not how to use a multimeter. This article does not apply to resistance or dB measurements.
Step 1
Understand the range. The meter has a range of zero to full scale. Zero (shown here) is always zero.
Step 2 Determine the voltage at full scale
It depends on the setting of the range switch. The meter is designed to give full scale when the voltage you're measuring matches the switch setting. Thus, if the switch is set to the 30 volt range, this picture shows 30 volts is applied across the inputs. Similarly, if the switch is set to the .1 amp range, you have 0.1 amps of current running through the meter.
Step 3 Remember that the meter is linear
So at half scale (shown here), you can just divide the range setting by 2. Here it is 150 volts on the 300V range, or 50mA on the 100mA range.
Step 4 Expect variations in scales
In this example, there are two scales, 0 to 1 and 0 to 3. Not all meters are like this. Some have 0 to 5, or 0 to 2, but scales are provided to match each setting of the range switch. Just find the one that matches the switch, then move the decimal point mentally.
This example shows 7.2 volts on the 10V range, or 216mA on the 300mA range. 
Here it's 36.5mV on the 100mV range, or 11A on the 30A range.
Tips
- If there is a mirror behind the needle, turn the meter left or right so that the needle covers its own reflection. This gives better accuracy.
- If the needle points below zero, then you've connected the "+" lead to a negative DC voltage (compared to the "-" lead). Note this, and reverse the connections to take the measurement.
- For DC current (Amps) measurements, the conventional current is flowing in to the "+" lead and out of the "-" lead when the pointer operates properly.
Warnings
- If the pointer goes above full scale, the reading is meaningless. Always select a high enough range that the pointer stays at or below full scale.
