@Roman743
My most important advice is to find a gestoria that is expert in tourist lets ("Airbnb's" is the current trendy term) and the entire tax and licencing laws surrounding it.
It is the single most valuable service you will ever employ. A good one will save you 1000's while keeping you perfectly legal and in good standing.
Other than that, my only other recommendation is to avoid being the cheapest. This will attract the least desirable guests and make it more difficult to make a profit.
Good luck, and happy hosting!