Why do I always fall behind in levels with experienced players?

Solution 1:

Playing carry is truly difficult when it comes to decision making. I play carry in my party most of the time (being the most experienced player) so I can give you some advice and simple rules to follow.

General lane behaviour in early game

If you are good at last hitting, maintain the creep equilibrium close to your tower but not in tower range. Ask your support to zone the enemy out so you won't get denied. That's the first step of not losing XP in lane.
Farming > killing. Don't ever waste time chasing or ganking or rotating lane as a carry. You only want to farm as much as possible. Take a kill when its effortless and won't make you lose more than 1 creepwave. In term of gold 5 last hit is ~200+ gold (same as a kill). If the enemy offlaner is running away with low health, just let him go, he's wasting time, not earning gold or xp which is fine enough for you.
Early teamfight are not your responsibility but your mid's one. Except if the fight happens in the safelane where you should be farming, never TP to a teamfight. Few carries can teamfight early on anyway (Maybe Gyro or nai'x can bring something to the table). But usually, a carry's skill set doesn't allow him to fight early. It's also your teams responsibility to not take early bad fight.
Depending on the difficulty of your lane, ask your support to rotate in the jungle (stack and pull neutrals) or gank the other lane. If you can handle the enemy offlaner alone and if your support leave, you will earn way more xp by being alone in the lane (they just have to ward the nearby jungle so you don't get ganked easily).
If you are having a hard time (versus a trilane or an very aggressive dual lane) consider rotating lanes, going to the jungle or run a defensive trilane.
Don't build a midas unless you have free farm. And remember : since the 6.79 using the midas on the jungle is not worth it if you lose more than 2 creeps in lane so be carefull when you use it.

The mid game

In the midgame, your mid player should start rotating and creating you more space. Allowing you to farm more

Profit of the early mid game (10/15 min into the game) to take down the enemy offlane 1st tower.If you can jungle (lifesteal, battlefury, maelstrom), you have now a safer jungle where you can farm creeps easily, letting the lane for your support to get some gold. Defend your safelane tower only when creeps come too close and go back in the jungle
You can start showing to teamfight, let people get focused first then jump in and kill the easy targets (support, squishy heroes, low life heroes). If you win the fight take the tower and go back to farm > Repeat.

In teamfight

Never ever (ever) start a fight on your own, you let the initiator (clockwerk, earthshaker, magnus, tide, whatever) do his job then you jump in. Unless you are void, then you better hit that perfect chrono.
Don't focus the enemy carry unless you are sure to kill him. At some point you can take the support fairly quickly and win the fight by outnumbering them.
If the fight is lost : ditch and run for your life. You are the most important hero on the team if you want to win so don't throw your life in a lost fight. It's the responsibility of your team to not take bad fights but its yours to not follow them in a lost battle (in this scenario communicating is the key).
If you are always getting focused : build a bkb. Low level player tend to want to farm their big damage items on carry (like crits, MKB, Mantastyle etc.) but those item are useless if you die within seconds. In those situation recognize that you need a BKB and build it.

Some tips to have in mind

If you are last hitting correctly and not being contested, you should have about 60cs (= creepstats = last hits) by 10 min.
If you are a squishy hero (luna, AM etc.) : get strength power treads before rushing a big item, it can save your life more than you think.
If you build treads, put them on strength, you will gain more survivability. Gaining 8 damage and 8 Attack speed is not worth the risk of getting bursted down.
Also a magic wand provide some minor stats and a great way to heal if you get ganked. It will save your life more time than you can imagine so just get one.