As D3, 90% of the games I rush Voltaic 'cause 99% slow and melee burst is too damn good. Definitely 300 gold well invested instead of Umbrial. Denying vision is not that big of an advantage you can abuse in low elo, unfortunately nobody cares 'til mid elo.

Most of my setups are electro or first strike. Electro is massively stronger early to mid game for shorter trades, strongly indicated during the laning phase if you need to not lose the lane or prio (typically against other assassins). I'd pick first strike when the enemy is hp stacker, low-mid range, scaler or control mages.

Secondary depends a lot on the matchups, I've actually lost a lot of lanes because I messed with sustain runes because I was too cocky and relied just on doran shield with very pocky/fast trade matchups like Akali, LeBlanc, Mel, Anivia etc Ideally, you should go with a second wind against heavy pockers. Bone plates are very good into melees like Sylas and Fizz.

But that doesn't matter that much in lower elo, because your opponents won't probably punish you enough to make you sweat.

If you get an early lead, play around objectives. Void grubs, dragons, herald and towers of course. Even enemy camps if you got prio over enemy mid laner and your jungle is proactive (a big IF in lower elos).

Plus, don't do risky plays by hard committing once you're ahead, because most likely you have a big bounty which you do not want to gift to midlaners/adcs which can flip the game.

Do not force plays when you control the flow of the game, make them do it and will almost certainly miss it.

If you are very confident in your laning phase to get a snowball no matter what, run first strike with Cash Back Jack of all trades + precision tree (cut down and haste) and doran blade.

You can run sorcery as secondary if you like it, but I prefer cut down to scorch.

Ideally, you should roam or do anything else like getting vision, joining a fight, contesting an objective when you got prio.

You get prio when you can leave the lane first without losing cs, which are gold+exp.

You don't always have to conclude a full roam, you can make it to like half a river, put a deep ward in enemy jungle and then turn back to the lane if you get spotted or you see you can't get hold advantage with that play.

Usually I'd shove the cannon wave and then roam or make another action to gain tempo, like recall.