At 1900 level the best thing to do is drill tactics and train your calculation.
At the same time, make sure your openings are solid.
These days the temptation is high to let the software do the heavy-lifting for you, but I think pure analysis over the board cannot be beat.
Stuff like Fritz etc. in my opinion is mostly useful for automatic game analysis and blunder checking.
Especially if you're already 1900.
Actually, when I was around your level (a bit higher), I spent around an hour a day training with the famous Ct-Art tactics training software and gained more than 100 points in half a year.
I also worked on my openings and tested them a lot in online blitz... I was a different player by the end.
Try this method if you like.
And if at all possible, play in as many tournaments as possible.
Non-playing is why my own play stagnated.