as a graffiti artist, to give you a tip on this. i understand you are just practicing, but if you wanna give it more of a graffiti feel rather than basic bubble letters, its rather simple. like when you draw the S. add a tail to the end part, just a tail like from a snake. or you can do things such as loops, whatever you wanna add on. like the E's. the bottom of the E that sticks out to the right, you can add to that to give it more of a flow. also maybe try putting human features into the letters, like the bottom of the A looks like legs, give it some feet. get creative, you can look at my gallery for some examples. hope this helps!