Need help as a mage...

I have a lot of trouble playing as a pure mage. Simply because of magicka usage. I mean, i usually get one hit kills cuz i had to turn down to novice difficulty, but still i have so much trouble conserving magicka. I play as an Altmer so naturally i have highborn and i use lots of magicka increasing items and upgrades. However i find that after a few fireballs are casted, i'm out of magicka. However when i try to use flames or frostbite, the enemy dosen't die that fast and usually has time to walk up to me and deal a highly damaging blow.

When i cast fireballs i miss a good bit cuz the enemies seem to take evasive maneuvers, that obviously wastes magicka. I end up using highborn in my first battle of a day.

I have Destruction, conjuration and restoration novice and apprentice casting and i try to get some other skill trees up.

I rarely level up and die a lot. I need some strategies.

Its really hard to play a pure mage. It always is because its hard to get enough magicka. There are some ways that at least worked for me.
Potions! There are many potions that are increasing your magicka AND the magicka regeneration. These can really help.
And then there is some staffs, like you said you use fireball. Get a fireball staff. They are pretty common. Traps is also very useful if you see that they are running up to you.
Then they will just explode in rainbow colors and sweetrolls!

Firebolt is actually more Magicka efficient with Single Targets. If you can be sure to hit several with a single casting, then FB, so I like to have them in each hand. Also, do you have Adept Destruction? You mentioned Apprentice, so I believe that may your problem. Frieball is an Adept Spell.

Also if you haven't already-upgrade you gear. Get adept robes od destruction and some rings, circlets and necklaces which decrease the cost of casting or increase Magicka. Do more alchemy-make potions yourself which restore magicka and health. When fighting mages use wards (timing is crutial as they use a lot of magicka and need time to charge).

Pure mage in skyrim sure is hard and there really isn't any crowd control besides a follower. Heck by the time I defend myself I don't have much magicka left for offense.

The key to my success was dremora lords..These guys are perfect for the squishy mage because they straight up have their sword in your enemies face stat!

So if you don't have that lvl conj then you should immediately get Sanguine Rose till you do.

I found thralls useful also but I only used them with twin souls so I could always have my lord.

I'm all out of potions. Especially after fighting the whisperer or whatever her name I've already got adept robes too. I had to kill Marcurio for them. Please keep in mind that i'm still barely level 10. And i didn't mean to say fireball, i meant Firebolt. The apprentice spell. I will try to get sanguines rose and i would try to make some progress in alchemy and enchantment but i'm busy just trying to reduce the cost of spells in any way possible.

if you get enchanting to a 100 and get all the bottom perks (and the top one if you want 2 effects) you can make a set of apeal (ring,necklace,hat and clothes) that reduce the cost of magicka of a spercific class of spell to 25%, which means waering all four pieces you can cast spells for 0 magicka!
i often do this with destruction and restoration, have thunderbolt in one hand and grand healing in the other!

I know about that exploit, but i'm still level 10. I can't have full enchanting already. And it's very hard to get 25℅ reduction.

A Flame Atronach adds a lot of firebolts to the fight, and also kites them around, so you can fall back, and let your magicka recover. At low level, it's especially challenging because of Magicka screw, especially if you're depending on a finite supply of Potions. For this, I have a few tricks to get past this phase of training:

First, don't get too Ambitious. Low level Warriors can wade in up to their nipples, and hack away, you have to recover, so don't just run yourself dry, and guzzle to get it back. Single enemies at a time, and to get your Destruction up quickly, focus on using Fire to burn undead. Cut through the Crypt overlooking Falkreath, there's a lot of Skeletons in there. Wolves, bunnies, deer, even if they run away, that's Experience!

Keep moving, let a Follower/Atronach pull some weight, and make those Bolts count. Firebolt travels slow (The only one slower is Ice Storm) so they have more time to dodge, so at long distance, Lightning Bolt might be a better choice. Ice Spike also slows them, which makes them easier to hit. So, don't use JUST the damage of your spells, but the other effects as well.

Talk to Drevis, and ask if there's anything you can do. He'll have you clean out the Magicka Wells, and a side effect is increased Magicka Recovery. There's 3 of them, so you can stack them together, or come back when they wear off. Only works once, but at low levels, they really help until you can get better robes/the Recovery perk.

Flames can be the most powerful low level spell if you don't hold it down, but pulse it in both hands, which stacks p multiple instances of the Afterburn effect. Alternate pulses on one side then the other to double your rate of Fire, it is a lot better than Firebolt, but much closer range. You can also hit 2, or sometimes 3 at once to double your damage output at the same time. This is also a lot less Magicka, because the casting cost is Per Second constant cast, and the short pulses cost a lot less each.

It's ok. I've begun pwning people now. I can regen magicka extremely quickly and i have loads of different spells.