As you start improving, it's very beneficial to start using a good Rubik's cube timer to keep track of and accurately time your solves. A physical timer like the ones used in competition isn't really necessary because there are many free online timers you can use that work just as well. The two timers I like to use are:
With these timers, you can reliably track your solves over time to see your improvement! They even offer statistics like calculating averages, means, and the standard deviations between your solves and averages.