Affect and effect are different in meaning, though frequently . Affect is chiefly used as a verb and its main meaning is ‘to influence or make a difference to’, as in the following example sentences:
The pay increase will greatly affect their lifestyle.
The began to affect my health.
The weather will affect my plans for the weekend.
Effect, on the other hand, is used both as a noun and a verb, although is more commonly used as a noun. As a noun it means ‘a result or an influence’, as in:
Move the cursor until you get the effect you want.
The beneficial effects of exercise are well documented.
Over time the effect of loud music can damage your hearing.
Growth in the economy can only be effected by economic controls.
The new policies did little to effect change.
The prime minister effected many policy changes.
The key thing to remember is that effect is most commonly used as a noun, whereas affect is typically used as a verb.