Hi Karle94, I had a quick look and I could see a lot of mistakes, these aren't all of them and if I am wrong forgive me I am tired and should really be a sleep.
Starting from left to right. Your are missing a boat davit, various items I'm going to call bollards, them where the secondary guns are located you have made the portholes to low, they should be above the height of the barrels. Now you may think that you don't have the room to do that but I think you've drawn the armoured belt wrong, which as a side effect has taken up some space. The height of the hatches for the secondaries should be increased to allow the correct placement of the windows.
on the mast you seem to have missed some masts and cables. Nest to A turret you're missing another 'bollard' and lower down some portholes just above the armoured belt. then Next to the forward most secondary the porthole placement isn't correct as they don't align with the surrounding features, the most forward two out of the cluster of 5 may be correct however. Then below the anchors you are missing either ladders or depth markings, I am sure if I checked on another photo I could work out what they are but I don't have the time sorry. At the flagpole you are missing a support leg.
I hope I have helped, I do like your drawings but I do find that you miss out a lot of detailing and its the details that make a good drawing into an excellent one. Study those photographs you will start seeing details that you missed the first time around.