If you got some money use it to buy premium, if you complete weekly quests with premium you get
8 keys, with the keys you can open vaults which give on average 3100 silver each so 24800 silver in total
Buying keys is a great way of growing your silver if you don't have premium.
you can often find them for around 2500 silver each.
You can use 8 keys extra per week over the ones you get for free
with the keys you can open vaults which give on average 3100 silver each so 4800 silver in total profits per week
Clearing all your weekly quests will give you around 35000 silver in total
This is taking into account opening vaults with your 7 free keys.
playing the market
Try and play the market, learn what items usually sell for, buy when you see
an item up for cheap and resell it at regular values.
converting bronze into silver
There are several ways of doing this.
One is to gather resources from the open world and sell them on the market for silver.
You can take this a step further by crafting materials of them or Unit kits and sell those for a higher profit.
Another way to make them sell for higher is to bring the exotics of one region to another and sell them there.
You can also convert your bronze into silver by salvaging horse materials for unbound materials which you can then sell on the market.
Holding Fiefs will give each member of the house a part of that fiefs treasury every week.
The more fiefs you hold and the larger their accumulated treasury the more weekly silver you'll get.
Attacking fiefs and winning the battle will instantly give you a certain amount of silver taken from its treasury