You need a source of electrical potential difference, also known as voltage (which is the technical term for what for you call "electric pressure"). The easiest and most common voltage source is a household battery. Hook up the positive electrode of the battery using a conductor (eg. a copper wire) to one end of your circuit and the negative electrode to the other end, and voila, you'll have electric current flowing through your circuit.
That would be the natural flow of electrons, from a negative potential to a positive potential.
An electric current is a flow of electric charge around a circuit.
A circuit in which electricity only flows in one path is called a series circuit.
if an electric circuit has potential difference. Electricity will flow only if an electrical circuit is closed.
The electrons don't actually move the electricity; the charge moves. The electrons slowly drift in the opposite direction from the charge.
An open circuit.
an incomplete circuit
Current Electricity
Electricity can flow in an electric circuit by a battery. The battery creates electrons, which flow through the wire, and then go into a light bulb. (That is how a light bulb in a circuit lights up.) A series circuit is a circuit with one wire that electrons can flow through. Also, there can be more than one light bulb connecting to the same wire. A parallel circuit is a circuit with light bulbs that have their own wire.ClarificationThe above answer, unfortunately, perpetuates the myth that current leaves a battery, and finds its way around a circuit. This is not the case at all. It is the load that 'draws' the current from the battery and it is the load that determines the size of that current.
Electrons
"circuit"
the current
goes around the circuit carrying electricity all around the circuit
electricity
Current
Electricity, this may be electrons in a direct current. In an alternating current the electrons stay where they are and it is only the energy that moves between electrons.
In a series circuit, if the current is broken the flow of all electricity stops.
current
If a conductor - such as a wire - moves through a magnetic field, a voltage is produced in the conductor. This may cause a current (if the wire is connected to an external circuit). This effect is used in generators to generate electricity.