Communication and planning is key.
I also managed to get to Gold I through solo queuing and just following one other teammate to use as a meat shield. Currently in Plat and only play with a full pre-made squad as I want all 3 of us to be alive when we enter top 5.
But again, talk and make a plan for your next move. Play based on everyone's strength that's on your team, I enjoy ambushing enemies or fighting in tight spots. So when I party up with 2 others, I lead and make the decisions on where to go and what to do. I accommodate those who love rushing into battle by setting up a spot to return to in the event that a battle is taking too long or we are being crushed. Back up plans are great as not all fights lead to success.
Also really utilize every legends abilities. Pathfinders great if you have the high ground as you can shoot ziplines in all directions attaching them to places the enemies can't reach, or by throwing smokes as Bangy on enemies so that another team near by can see the smoke and rush it, making room for you to 3p. Also don't forget to use Ults as much as you can, they recharge at a nice rate if you pace yourself, and plenty of accelerants are always laying around.
This is how I'm making my way up to Apex Pred.
Worse case though, wait for respawn ships and rack up those easy kills