Newbie to Using OPKs (Advice appreciated)

♡ l o u • k e i r a ♡ l e o
Hello everyone!
My partner and I have been TTC for at least 5 years now (on and off) for our second baby. In this time we've not used protection but also not been really TTC giving it our all, but now is the time!
I started using OPKs for the first time yesterday so have done two in total. The picture I've added is day one and then today. The line is slightly darker today compared to yesterday but I'm aware the line needs to be just as dark as the control line. 
While I know this, does the fact it's darker mean as the days go on it should continue to get darker? Does it indicate I'm getting closer to a positive result? 
Any information would be greatly appreciated as I'm so new to OPKs. 
Thanks!