Would need to see your roster to give advice 

The quickest fix  is more speed  on your gear

speed  boots primary  / rest of gear sub stats with speed 

But aside from that yes what ShortOnSkillz  said

I was in same situation. I broke through to Gold this morning and worked up to Gold 5 in less than 2 hours. Those in Gold 2 and 3, I do not think could win a match in Silver 3.  

I added Connely as my lead. Had a lot of speed (267) . She puts everyone asleep. Then follow up with a decrease Defense and Nuke. Stay away from teams with arbiter in lead or one's that have Deacon Armstrong or Pythion.  You may have to refresh a lot . Once you hit Gold,  it is really easy.