Others are correct that you want to stick to maining 1-2 champions but the pick really comes down to who you enjoy and are good with. Specific picks don't really matter all that much you just need to learn the pros/cons of your pick. If you are a split pushing champion then you going to want to learn more about spilt pushing and when to do it. If you more of a team fight champion then you going to want to work on when to force fights, who to focus, etc.
Top my worst lane so it's hard to give you tips plus I am only gold 4 but below are some general things I have learned over time that help me climb to gold after being stuck in silver for years.
-
Learning to rotate is important. A lot of times people will only go to their original lane like first 20 mins of game. This works but what happens if your entire team goes bot and you have enemy mid/jungle pushing your mid turret? Well if your lane is pushed top you could 1. try to take top turret. 2. Go mid and clear waves so you don't lose mid turret. 3. Maybe tp bot and help. There is always choices to make but a lot of times in silver players just brainlessly go back to their lane without looking at other lanes to see if they could help cover.
-
This leads to second point of map awareness. Try to look at minimap often so you can see where enemy players are. If you see 5 enemies on minimap you know they all accounted for. Then it turns into how many enemies alive/dead, where are they at, and basically trying to predict their movements and making plays around those predictions.
-
Csing is important.
-
Learning when to trade, when to deny cs. I will admit I am really bad at this but these higher level concepts worth exploring to get better at laning. I main jungle so it's a little different but again you need to learn match ups and how much damage you do and learning when and how to trade with enemy.
-
Taking objectives. A lot of times in low elo a team fight is won and then players don't push their advantage. Most the time you want to push lanes and take turrets as turrets = more gold = closer to killing enemy inhibitors = closer to killing enemy nexus. But sometimes it pays to take a dragon or baron depending on the situation.
-
Continuing off 5 as important it is to push objectives you also need to know when to back off. Lots of times 1 team will win a team fight, push mid and take inhibitor. Enemy team respawns and instead of backing they will try and fight the freshly respawned enemy team and die. This happens all the time in silver and best thing to do is realize this, ping your teammates to back but realize a lot of the time they will just stay and die. Instead of dying with them or for them just back and push other lanes or solo dragon or take enemy jungle rather than dying with your team. Also, a lot of silver players try to force dragon fights. Yes... you want dragons. But they not worth dying over. If you see 4-5 enemies at dragon it's dumb to try and force 2-3 of your teammates to go fight it especially if you already behind. As a jungler it is important to know when to go for steals, when to take objectives, when to try and force some fights. A lot of the times I get flammed (especially on silver account) for letting enemy take a dragon. But I know its not worth trying to go to a dragon (usually an ocean drake for w/e reason) with like 3 teammates vs 5 enemies. So basically... knowing when to pick your battles.
-
Warding.
-
Clearing waves. When enemy pushing if you can kill the minions then enemy cannot push your turret without taking damage. This more important for adc/mid to focus on especially mages. But if you a ranged top or have the chance to kill wave try to clear it so enemy team has to wait longer to hit turret. Also, sometimes it's worth giving up turret. I see a lot of times especially in silver where 4 enemy players will be pushing mid. 1 person will try and stop them and just die instantly to tower dive. Then another teammates goes in and same thing happens. If you can clear the wave safely then clear the wave but if not just back off and wait to fight at another turret with your team.
-
Lots more to learn these just some basics to focus on. Use op.gg, champion.gg and other sites to learn strong builds for your champions.