At your level you have alot of spawns available for yourself. Depending on what you want to achieve they differ in quality though.
Trululu already mentioned some/most of them, but let's dive deeper and explain some. I will divide this into three categories.
These spawns will net you good experience but the profit won't be great.
Oramond West(with quara raid) - Don't even bother coming here without the raid. You wanna take thunderstorms here. At 300 you can use magic level / earth protection EQ - probably an upgraded gill set. Basically you just walk around the entire place and lure as many mobs as you can behind you. You won't need mana shield 99% of the time. Avoid side stepping as you will get paralyzed a lot. No biggie if it happens since chances of dying are low but take care. To maximize xp/h you don't pick up any loot which results in massive waste. With the "new" auto loot feature you might just click bodies while walking by to help with that.
Banuta lower floors - Similar to oramond west but a little more dangerous. Sub optimal for druids because both of your UEs don't really work here which might be an issue since all of the monsters run on low hp. Gill necklace highly recommended. Depending on how comfortable you are hunts will result in minor profit.
West Raid(Oramond Factory) - Also known as Wildlife raid. Hard on 300 but doable. Take earth / physical resistance and avalanches. Unless you are very comfortable in that spawn stay near walls to not get boxed by 8. Once you feel like it is getting too much find a spot where only 3 can hit you and you'll be fine. Profit/waste somewhat depends on the price of silver raid tokens on your server.
These spawns focus on loot rather than on experience
Glooth Bandits - El Classico of mage profit spawns. With the increased respawn rate added recently this has turned out to be a very good spawn even up to higher levels. At 300 you can go with full magic level equipment and kill through them really fast. Big upside of the spawn is that you can quickly sell loot and refill. Downside would be the required access to the spawn which is a boring grind. Needed to unlock other top tier spawns as well though, so its worth it.
Demons - Probably the best option would be goroma, edron and/or yalahar could be viable as well though depending on how chill you wann hunt. Mostly viable while you're on the task. Profit is really good without it as well though. Make sure to make use of the strong ice wave as it hits them really hard. As you will only kill demons in those spawns you might wanna see if you can get your hands on loot pray for the time you spend there to maximize your gains.
These spawns are a combination of good experience and profit
Falcons - The absolute power house of all spawns for mages right now. They insanely slow movement speed combined with big amounts of experience and loot make them insane for mages. Obviously this makes the spawn really crowded on most servers as well. The best spot to hunt them is in the big room where the boss tp is located. You have tons of space to run and a lot of monsters to lure. Consider using energy bombs to lure them over while attacking with avalanches as at your level it will take a long time to kill them. For equipment you should probably be on mana shield most of them time. Use physical & earth protection gear to help with your mana.
Asuras behind the mirror - Another packed spawn. Not as insane as the falcons but still a combination of both great experience and profit. Spawn is dangerous at times because of narrow corridors and their ability to make you drunk. Avoid and/or lure the few true asuras into passages which you do not hunt and you are good to go. Depending on how comfortable you are you can go without mana shield. Death & mana drain protection recommended in both cases. Use Avalanches (or, if you really want to kill the ice asuras, thunderstorms) here.
Carnivoras - Still a new spawn. Not exactly sure how much experience you can make there but the first impression seemed good. At this level i would recommend hunting the second floor as the menacing carnivoras can hit really hard. A mix of physical protection and magic level equipment seems suitable here. As there is a lot of loot you will have to figure out how to balance your supplies. You will probably run out of cap before running out of supplies in your first few hunts. Try adjusting and figure out the best way. Use GFBs here.
Gazer Spectres - Another new spawn added in the last update. Pretty easy to hunt if you keep your distance. Their extreme vulnerability to ice makes the very appealing for a druid. Life drain / fire resistance recommended. Other than that just keep an eye on the traps on the floor which make you drop down to another area (free of monsters though, you can use it as an escape mechanism as well). Avalanches are the obvious choice for this spawn.