DON'T GANK LOSING LANES. Just trust me on this. If top is 0/4 and mid is 2/5 and bot is 5/2. FOCUS BOT LANE AND ONLY BOT LANE. The only exception is to keep them from taking towers. However no one is going to take tower within 10 minutes. That's rare AF.
Just think. You see mid is constantly pushed to the tower and has no wards. Same with top. Why would you gank the lane?
It's as simple as winning lanes help losing lanes. so EVENTUALLY bot will leave and go mid and top. same goes for all lanes.
And if all lanes are losing. Go for objectives and focus the lane that's doing the best.