An Airbnb revenue forecast is a month-by-month projection of occupancy, ADR and revenue for one property, set beside comparable listings. Buyers use it to test a purchase, operators use it to check an arbitrage lease, and hosts use it to set targets for a live listing.
What I plan around in Barcelona: Mobile World Congress; Primavera Sound and Sónar; Beach season and cruise arrivals; FC Barcelona fixtures. Guests I price for: European city-breakers and cruise passengers on 2 to 4 night stays, with longer summer stays near the beach. Where I start: Licensed tourist-apartment pricing, MWC premiums that start a year ahead, and length-of-stay discounts for the shoulder months.
I set your Barcelona pricing so MWC, Primavera Sound and summer dates are loaded with premiums and minimum stays, shoulder months use length-of-stay discounts, and Airbnb, Booking.com and Vrbo all show consistent rates and tax, while the calendar respects the city's rules on which licence the flat holds and how it may be marketed.
The service in general is described on my airbnb revenue forecast page; this page covers how I apply it in Barcelona.