I know this is going to sound a bit blunt, or offensive maybe, but...
1.) Don't be dumb?
https://www.youtube.com/watch?v=6ywhB-2h2AE In bronze it really doesn't happen like this so perfectly, but in professional and higher elo its a lot better.
2.) Don't go jungler and be stupid, I know with the new role system you are like Okay I will try jungling, but let me tell you the problem its happening a lot its an infestation and its costing me, and 3 other players lots of games (Junglers who are either Griefing) or have no idea what they are doing.
. By definition (Don't run into a lane without thinking about what you are doing first, you should always ask yourself before going in.)
1.) Am I going to be helping my team-mate?
2.) Does the lane need a gank.
3.) How much HP does the enemy have.
4.) What skills does the enemy have (Is there flash up etc.)
5.) Does my ally have (CC) (Snares Etc) (What skills does I have as a jungler.)
6.) If unsure ask in chat first before just throwing a user off. (This has happened 4 times today at least) and its very stressful not being able to really do anything
The reason this is all important is because there are many games where a jungler just runs down my lane before level 6 this is a huge issue because #1, You take XP from your laner, sometimes its not a problem, but for the second issue you contribute nothing and chase a low HP enemy off when your lane is about to get ahead and make them back, the problem with this is your lane player might be countered by the enemy and the enemy has more CS so if you just made them back when your ally could have gotten ahead you just ruined the game hard for your allies and its more likely they feed or have to roam/lose lane.
The reason for asking all these is because it determines how likely it is to be successful, as well as if you should actually gank or not, of course there are sometimes if a lane is already doing badly and giving kills you should try to do something, but (Griefing) is a report worthy offense and doing this upsets me as a player, and other people and you will get reported for it often, because you ruin those trying to advance who have skill to advance but you drag them down yourself.
3.) Understand the importance of Cool-Down Reduction, on Leona, Sejuani, for example you need 40% or 45% with new masteries best way to go, you should be building a "Frozen Heart a lot of the time" and "CDR Boots" at least a lot of players talk back to me about this but in bronze when ur team screws up and ur on cooldown but ur game is lost because ur ult is a 60+ Second cooldown instead of a 36 second cooldown then you just cost the game for everyone?
4.) As Leona seriously please don't leave until your dead, this is a bit of an overstatement, but a lot of leona players run, you should have 40/45% CDR you should be able to effectively stun lock an entire enemy team or key players that are needed to be done.
5.) Focus the ADC/ APC isn't always the best thing sometimes you need to focus the support.
http://www.lolking.net/summoner/na/23564572#runes Look at rune page #17 as an example of what I like to run as a support what little I play it.
6.) Use "Quick Cast" In options if you don't know what that is look here.
https://www.youtube.com/watch?v=hSssIe-6TZM
. You should be able to Move, and cast skills at the same time.
Use Alt + E for example on nidalee to heal yourself or on other various characters for self casting ability.
Use Flash + E + Q +W on Leona or other various champions to go into fights.
Learn to ward jump on Jax, Katarina, etc.
https://www.youtube.com/watch?v=COMxyqKwqR8
Learn when to use "Move Speed" to win games especially on assassin based champions.) (No I don't mean move speed items fully but like "Boots of mobility", and AP Move items like "Lich Bane" and such.
7.) Last thing Don't 
unless you know what you are doing half the time you will just be one less useful on your team and, throw games out the window easily especially when u screw up the ultimate in group fights, Yes really I get players who do this to me, even 
players using their ultimate to troll, a good fight we would win gone to waste because it is misused (Another reason to report players.)
8.) Don't ask for reports, or Threaten to report (its report worthy itself.)
So if you want to actually advance in Ranked Good Luck, if you actually like jungle and are a god jungle and you get a decent lane or two who can also play then you can easily advance.
