We went to the sea Good! You could also say 'A trip to the sea' (海に旅行）

I enjoyed spending time with my friends yesterday. 'Play' sounds a little childish, 'spend time' is better here.　
It was very fun and tiring.

First, I had carbonara at an italian restaurant.
It was delicious:)

Then, we went to the sea.
The sea was very far away! We walked for about an hour.
It was so hard. Maybe 'it was quite difficult' or 'it was quite tiring' would be better here.
Despite this, the sea was very beautiful!!
We watched the sea and fished for a couple of hours.

Then, we ate hamburgers and fries at McDonald's. It was delicious! 

We made some good memories.

Good! remember to use 'for' when talking about how long you did something, and remember to use the past tense.

We went to the sea

I enjoyed playing with my friends yesterday.
It was very fun and tired tiring. 
First, I had carbonara at an Italian restaurant.
It's It was delicious:)

Then, we went to the sea.
The sea was very far! We walked about an hour.
It was so hard.
But, the sea was very beautiful!!
We viewed and started to fishing on the sea for a couple of hours.

Then, we ate hamburger at and fried potato (do you mean french fries?) in McDonald. That was very good!

Made some memories.