There are two types of graphs:

First Category: Line graph,Bar graph,Pie chart and Table
Another category: Process, Diagram,Flowchart and Map

The first point that every candidate has in their mind is, what would be the FORMAT of WRITING TASK 1. There are numerous points that one should focus on which are discussed below:

*Timing of task 1 is of 20 minutes.
*Word limit is 180 – 220 words.
*Tenses are the main concern; mainly Line graph,Bar graph,Pie chart and Table are in past tense.However, check once in a while whether it is a present or future tense.

Format of Line graph, Bar graph, Pie chart and Table

Introduction: What+Where+when. Data has been calibrated in ‘percentage/million etc’.
For example:- The line graph depicts the information about the overseas visitors who came to the United Kingdom from 1980 to 2008. Data has been calibrated in millions.

Body paragraph 1: Turning into details,

Body paragraph 2: Probing into deeper details,

Overall,it can be seen that
Note: Don’t mention percentage/year/data/figure etc, because already explanation is explained in Body paragraphs.

Format of Process, Diagram, Flowchart

Introduction + overall  (Combine introduction and overall)

For example:- The diagram reveals the information about the manufacturing of the bricks in an industry. Overall, it can be seen that there are seven stages, beginning from digging up of clay to final at delivery of the bricks.

Body paragraph 1: In the initial steps/stages,

Body paragraph 2: In the subsequent steps/stages,

Note: Use always present tense:
          Present indefinite tense (Verb 1+s/es)
          Present passive(Is/are+verb 3)
          Present Perfect(Has/have+verb 3)