A good way to vary the language you use is by learning different word forms.
Verbs and nouns
- the number increased
- there was an increase in the number
- UK house prices fell
- the UK saw a fall in house prices
Adverbs and adjectives
- sales rose dramatically
- there was a dramatic rise in sales
- with sales reaching €3 million and €15 million respectively
- with sales of the two respective products reaching €3 million and €15 million
Use a dictionary to find some different forms of words that you already know. This is a good way to improve your English in general, not only for writing task 1.