Design Webs

I’ve been running a small apartment site for 16 years. Every year when the rental dates approach in February, March — The large multinationals of the sector, crush me in the most searched positions in Google. Only, on those dates, how do they do it? In a matter of a month, they reach the first position. I try to increase my backlinks, blog comments, … anyway what I can. I would like someone to explain me, how they take away my top positions so quickly. My website is:
apartamentos en zahara de los atunes