Tell me, without looking it up. the amount of damage smite does to monsters at level 15:P
Which part of sona's ult ACTUALLY stuns you?
What BASE % of damage does a target being isolated give to a Khazix Q?
The best way I found to improve is studying. As lame as that sounds, stopped watching streamers for fun, and really started watching for their details. The reason they walked between hitting jungle minions. The reason they flashed in certain directions. Most importantly their judgement calls when calculating the damage enemy champs do, the damage they do, and their personal ability to dodge skillshots.
Aside from studying, focus on not dying, and NEVER go on auto pilot mode.
Always be thinking: "DO I go in, or get out. Can I kill them and escape effectively, where is the enemy jungler right now (hint: In silver he's always the exact opposite side of the map from you:P"
Also, learn the current meta. right now its kind of tricky, Many would argue its still an ardent censer meta where the jungler needs to play support/peeling style junglers to get the adc as fed as possible. I personally think we've left the ardent censer meta, and started creeping back into a tank meta. Galio, Urgot, hell I've even seen nautilus make a small return. Just study whats working for the majority of people, watch good streamers, and learn every aspect of the game.
by the way the answers are 850, the tip of sonas ult is the only part that stuns. , (if you walk into the yellow ray as it is coming out, you will not get stunned. Kha zix Q (I don't play him much, nor have I seen him very often) but i'm pretty sure its 50% base additional damage to isolated targets. Knowing these small details give you the insight when it comes to fighting the enemy. Macro play is much more important though, you should know how much gold towers give, how long baron/elder lasts, how long inhibs are down etc.
Im only gold 5, but I've climbed solo queue, and reached gold on two separate accounts using the same strategy, so take what you want, and leave the scraps for anyone else trying to climb:P Good luck!