Introduction
In the first paragraph we write our opening remarks and the reason for writing our letter.
Main Body
In the second paragraph we describe the location of the house and give details of the rent.
In the third paragraph we describe the exterior of the house (what it is made of, garden, etc).
In the fourth paragraph we describe the interior of the house (e.g. floors, rooms, furniture, special features, etc).
We start each main-body paragraph with a topic sentence i.e. a sentence which introduces or summarises the paragraph.
Conclusion
In the last paragraph we write our closing remarks and sign off using Yours, Best wishes, etc + our first name.