This is really pretty! I think you've done really well with the writing here; I especially love the word "idea", and the way you've coloured it. It really stands out from the rest! However, I think you could be a little more careful with your slanting; for instance, the word apple is written noticeably different each time. Try practicing some letters that you may struggle on over and over, it should help train your hand a little more! Hope I helped!
Usually I either make thick black lines on another piece of paper and put it underneath to show through (this doesn't work when I'm using higher-quality paper to write on, because it's less see-through) or I make faint pencil guidelines on the piece itself. But because I draw a baseline, a line for the top of the "middle" bit, a line for the ascenders and a line for the descenders for each row in the piece sometimes I get put off doing more calligraphy pieces because I can't face the thought of measuring out and ruling more lines!
The trouble comes really when I have to redo the piece because I've made a mistake. Then I have to start drawing lines all over again