Hola hola!  Hace mucho tiempo que no nos vemos! :P

Bueno, voy a leer tu trabajo, me parece muy interesante.  Voy a escribir las correcciones en rojo y las sugerencias en azul...

Holidays

This year I decided to go to the Canary Islands on holidays. Previously , I’d been to Tenerife and Lanzarote, so this time I took booked/bought tickets for Gran Canaria. (en inglés se dice 'to book' or 'to buy' tickets).

 
I was with my boyfriend, we stayed in a hotel in the capital which was next to the beach.

For all the people (anyone) (no está mal escrito, pero se dice normalmente 'for anyone'...por eso, hay que poner el participio 'want' en singular - wants) who wants to go to Gran Canaria it is important to know that in the north of the Island the weather is worse. The best weather is on the south side, there the sun always shines. No está mal, pero se puede decir 'where the sun...'

The most beautiful beaches are on the south, the beaches have golden sand and the colour of the water is turquoise. There aren’t a lot of beaches with golden sand, most of them are black or with stones. They have charm but I prefer white or gold sand.

On the other hand (Por otro lado = On the other hand - pero normalmente solo se puede eso después de haber dicho 'On one hand'...es como 'Por un lado...por otro lado...'), there are a lot of beautiful views, but you need to spend a lot of time driving a car. You can drive through of along the road and stop in a at different viewpoints, some places are really beautiful.

A thing that I recommend if you go to Gran Canaria is to go to the beach Gui gui, is the paradise Solemos decir 'It's a paradise' o 'It's paradise'.

It's very difficult to get there, you have to walk for four or five hours.

En español se dice 'Es muy dificil' sin pronombre, pero en inglés hay que usar el pronombre.  Puede ser 'he', 'she' o 'it'.  Puesto que estás escribiendo de algo general y sin género, hay que usar 'It' para decir 'It is'...ya sabes que nos decimos 'It's' como abbreviatura.

The people recommend that you do camping for one night on the beach, (También se puede decir 'People recommend camping for....'  En español se dice 'La gente' pero en inglés, si no estás hablando de personas específicas, no se usa el artículo.  Se puede decir 'People...')

because you will be very exhausted to do this in only one day. And don’t forget your trainers, you will need it them ('Trainers' es una palabra plural, por lo tanto el pronombre aquí es 'them').

Another interesting thing that you can do on the Island is go to see dolphins. There are a lot of excursions which provide this service. I didn’t have luck but I could see a tortoise.
If you like to do sports you will be able to do surfing. I did it and it (como antes) was a good experience, it wasn’t be easy but it was better than I thought. I’m sure that I will do it again.
Although it was a good holidays, for me the best Canary Island from Canary is Lanzarote, and if you want to go to Islands from Spain (se dice normalmente 'the Canary Islands) I recommend that you go to the Balearic Islands, that’s they're wonderful.

One island - 'that's wonderful' o 'it's wonderful'

2+ islands - 'they're wonderful'.

Qué envidia, Nuria.  Ahora quiero ir de vacaciones....un momento...estoy de vacaciones!

Muy bien escrito!  Estoy impresionado, y como de dije, tu inglés es muy, muy bien!

Bueno, yo he escrito bastante, pero solo para tratar de explicar algunas cosas.  En realidad, son detalles bastante superficiales, y podía entender perfectamente lo que quería decir en todo el ejercicio.

Sigue así!

Leigh

Holidays

This year I decided to go to the Canary Islands on holidays. Previously , I’d been to Tenerife and Lanzarote, so this time I took got/bought tickets for Gran Canaria.
I was with my boyfriend, and we stayed in a hotel on in the capital, which was next to the beach.
For all the people anyone who wants to go to Gran Canaria, it is important to know that in the north of the Iisland the weather is worse. The best weather is on the south side,; there the sun always shines. The most beautiful beaches are on the south,; the beaches they have golden sand and the colour of the water is turquoise. There aren’t a lot of beaches with golden sand, most of them are black or with stones. They have charm but I prefer white or gold sand.
For On other hand, there are a lot of beautiful views, but you need to spend a lot of time driving in a car. You can drive through of along the road and stop in a at different viewpoints,. sSome places are really beautiful.
A thing that I recommend if you go to Gran Canaria is to go to the beach Gui gui, it is the paradise. It is Is very difficult to get there, because you have to walk for four or five hours. The people recommend to do camping for one night on the beach, because you will be very exhausted to do this taking this trip in only one day. And don’t forget your trainers, you will need it them.
Another interesting thing that you can do on the Island is go to see dolphins. There are a lot of excursions which provide this service. I didn’t have any luck but I could see a tortoise.
If you like to do sports you will be able to do go surfing. I did it and thought it was a good experience,. iIt wasn’t be easy but it was better than I thought expected. I’m sure that I will do it again.
Although it was a good holidays, for me the best Iisland from Canary of the Canaries is Lanzarote, and but Iif you want to go to the Iislands from Spain I recommend you go to the Balearic Islands, that’s they're wonderful.

Great job! My corrections are fairly minor, and a few are just stylistic.