In adhering to the word limit, it is always a good idea for you to roughly plan first how many sections or paragraphs you will need for the essay. From there, you will be able to estimate how much you have to write for each section or paragraph.
The general rule of thumb is to allocate 10% of the word limit for the introduction and 10% for the conclusion. This rule will leave 80% for the body paragraphs or sections.
Here is the breakdown:
Introduction - 10%
Paragraph 1 - 20%
Paragraph 2 - 20%
Paragraph 3 - 20%
Paragraph 4 - 20%
Conclusion - 10%
In writing a dissertation, the allocation of word limit might differ slightly. The weightage depends on the depth of each chapter. For example,
Introduction - 10%
Literature review - 25%
Methodology - 15%
Findings - 20%
Discussion - 20%
Conclusion - 10%
Remember that normally the references and appendices are not included in the word count.