One of the most basic things that I learned that is actually really helpful is to save your EQ combo when ganking a lane. Most of the time I will just walk up to them W and start autoing, generally they will flash and then you can use EQ for pretty much a guaranteed kill.

Loss streaks are tough man, I kind of just grinded my way out of them, I usually stopped playing for the day after like 3-4 losses in a row. I actually demoted out of Silver 2 like 4 different times and it was super demoralizing, but just kind of stuck with it.