Everyone gets paid on objective waves, so focus on contributing with them. For hacks and escorts, always be present in the circle asap. For the other objectives, either focus on the pizza or devices, or draw aggro from those spots (without killing enemies, as they will only re-spawn in a spot probably worse for the objective)
Don't chinse out on using in game consumables, especially in later waves. Too many times games will wipe because that 1 or 2 players decided not to use a med-gel on wave 9, which is absurd, considering the extra credits received for completing the wave 10 objective.
Ammo, armor and weapon consumables plus gear makes a very large difference to players performance. Ammo being by far the most important, as these will provide combo detonation capability or armor mitigation or shield / barrier mitigation.
Having said that, I have started many accounts, and go to Gold by match 3-4. Most times I will not have gear or anything but 2 of each in game consumable. There are some kits experienced players can use to be effective without ammo / armor / weapon consumables, these are the HA, HE, phoenix kits, any flamer kit, slayer, shadow and to a lesser degree the Novaguard. Ammo and armor consumables always help though ...
It's actually rare for me to be kicked from a Gold lobby with no consumables, surprisingly; I certainly don't blame players when it does happen. One of the reasons I like joining a GIP on a new account so I can prove myself in game before we get back to the lobby and other see I have no gear or consumables.
But really, are any players in the know going to kick a low N7/CP player with no consumables with a name like 'WorkinAsIntended'?