Pretty much the title. You're playing Zed, Leblanc, Kat or some other. Someone who just goes ham in a team-fight. But for whatever reason you can't really dive. They have too much peel, you don't deal enough damage, or just you flat out die before you can get your burst off.
So what do you do? How can you be useful?
Make picks.
If the enemy team is bunched up, splitpush.
Poke and wait for someone else to initiate. Ask them to if you need. Make sure to keep watch of enemy positions to catch them out whenever you can.
Generally, any team defenses can be broken with the right play. Always remember that you have 4 other members as well.
If you're laning, you're going to want to win that lane by denying, outrading, and harassing. Make them pay for not letting you dive by whittling them down. If you still can't dive because they have a skill that counters diving, wait for jungler support. 2 v 1, no matter what they do, it's 2 skill sets against 1. Unless they're an AoE terror for example 
, you will have to play extremely careful. Here's an example of what I meant by AoE terror: https://www.youtube.com/watch?v=by5kmWvyvfA
The Champions you mentioned are big damage dealers, so the obvious solution would be to buy penetration. But if they got reseistances and 
, it's going to be tough regardless.
If you can't dive? Then don't. Wait for an opportunity, the beauty of assassins is that they can get denied all game, but when the pick off that one champion, whole teams can crumble when you break their formations.
if you can't dive to get the squishies in the teamfights then split push and force the enemy team to send 2 members to deal with you and then your team will have a 4 v 3 in their favor
How are you not able to dive as those champions?
This is an actual question.
