Artifical's post is correct, bards are somewhat unique. The value in a bard is they are great for learning areas/items. That's the main take with from playing one, is the information you can gather. Their playstyle is more like a paladin/shaman than a mage.

Life is easier as a bard than a necro without a doubt. A necro is more of a finesse class by far. For one, stay invis at all times, just because it might prevent a few people from attacking you. Necros have a lot of inherent enemies. Every goodie, rager app, outlander, is pretty much going to attack you on sight. So keep an eye on the where pk, and try to avoid getting caught by them in vulnerable situations. As the necro, you want to control engagements and keep them on your terms. If a giant runs up and bashes you, fleeing is probably your first command. Experience helps vets size up enemies pretty quickly. A guy that is hitting for CAPS damage in the teen ranks is probably nor a fight you want as a lowbie mage. Don't feel the need to fight people on their terms in the low ranges, try to mostly fight on yours. As you get up in rank, you'll be better able to handle the random encounters and dictate the flow of a battle. But in low ranges, this is going to favor the melee chars more.

I would advise any mage newbie learn how to get a hp set of gear. You should be able to get about 10-20 hp a slot pretty easily with very minimal effort. Also as a lowbie know which areas are frequented by ranking people and just check them for gear on the ground. You can usually find two sandy cloaks just sitting on the ground in the Araile for example. Things like hit and dam are pretty negligible, you rely on spells for most of your dam output, so focus on hp gearing and save spell.

Against mobs, level matters. If something is too tough at level 15, at level 20 it might become noticeably easier. Never play as if you have to get the best things you can the earliest you can. You can just as easily spend two hours ranking to gain 4 or 5 ranks and killing what would be a difficult mob in 5 minutes as opposed to spending an hour trying to kill that same mob at a lower level.

Don't let gear be your only focus though. Some vets will have very nice gear at low ranges, either through gifts/pk or just because they spent the effort to get it. But the majority of chars are not running around with hero sets in the teens. Never forego a good ranking opportunity because you want to spend time trying to improve your gear. The higher you go, the easier it is to gear. By the high 20's you might consider doing a gear upgrade, and then in the 40's you start gathering your hero set. A possible way to gain gear knowledge is asking your ranking mates. It's pretty rare for three newbies to be grouped together. Usually there is a guy who has a bit of experience, so engage with them.

Ask group mates and such for suggestions on things you could replace your gear with. This is two fold. One, while ranking, it gives you things to talk about and discuss in the downtime of recovery. Ranking can be very tedious and boring, so adding in some conversation is generally a nice way to break up the monotony. Second, you get the benefit of the information, and they may also end up helping you get the gear. If I tell you to just visit the dark elf and get the tiny iron dagger, that info isn't going to be of any use to you if you have no idea where they are.

While not all vets are overtly helpful, you'll surely encounter a few that would enjoy leading you on an expedition to a new place. It's an RP opportunity for them as much as you, and that can be more fun for everybody than killing elf number 563281 in the vale.