I got a sloop when i started so i would plunder other player and npc. but i run out of gold so quick i can't upgrade my sloop or any thing else so i wonder if anyone have a tip to get more gold so i could upgrade sloop and other.

Work as a porter. Click on Court and it will be on the right side. It trades turns for money.

The other option is to request a loan for about 50-100k from the banks, and continue plundering only NPCs.