It is important to write formally in a discursive essay. This means you should write in complete sentences, using full words and expressions and standard English. Contractions should be avoided. For example, 'is not' should be used instead of 'isn't'.

It is advisable to try and avoid expressions like 'a lot' or 'lots of'. More formal expressions such as 'many', 'much', 'a number of', or 'numerous' are more suitable for discursive writing.

Do's and Don'ts
DoDo not use
Write in proper, complete sentencesAbbreviations (ie/eg/etc/UK)
Use complete words and expressionsContractions (isn't/don't/won't)
Use proper, standard EnglishSlang (bloke/geezer etc)
Colloquial language (mate/bolshy etc)
Move on to Test