1. Keep in mind the V shape!
This is an essential thing for the eurodance style. Notes go up and down, up and down and so on. This is what gives the dance movement!
There are 2 variants:
The UP V form (down-up)
The DOWN V form (up-down)
2. Use the 2 notes trick instead one (works good especially when working with 1 octave distance between notes)
3. Watch for continuity between the bars!! - when changing bars make sure your notes don't jump too much! :)
4. Modify the pitch for selected notes
Use the following trick when making riffs:
Take some notes from the standard V shape and move them up or down - you will find great riffs!
Good luck!