I find that everyone can develop their own style, unique to themselves, and yet at the same time, still be pleasant to the eye. One thing is to practice your cadence or the spacing between letters. Also, consistency between the same letter is the key. There can be different variances between letters if you're using a linked cursive script; for example, letters following an "o" look different than say following an "i" because the joining element is at different heights.
To practice this, I usually copy words. Long words, with many I's and O's. Poetry. Anything that inspires you to write. I have certain words that I do love to practice: titanium, electrocardioversion, osmosis. Those, of everything I find, help with my cadence and linkages between letters, and help develop the muscle memory.
What I don't find helpful, is the thickness of your lines. A bold nibbed line hides many details. If a script looks lovely with a thin-nibbed pen, it will look nice with a bolder nib as long as you can still make out the details.