I have around 150 hours in Dota 2. I know most characters move sets and skills, and I last hit rather efficiently. (Around 85% of the time when not near any tower). I usually play carry, and I do rather well in public matches I get matched up in. When I play with my friends who have significantly more experience than me, (Around 600 hours each) I ALWAYS fall behind in not just XP but gold. I'm around level 8 when everyone else is 11 and my net worth is lower. Even if I have significantly more last hits than them, I'm always behind in gold from team fights I suppose. I show to team fights late, and never get any assists which may be a problem. And specific details that can help me catch up in level and stop being targeted in team fights?
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
The mid game
In the midgame, your mid player should start rotating and creating you more space. Allowing you to farm more
Some tips to have in mind