If you are using b'cream to write with -consistency is very important. You don't want it too thin, but definitely not stiff.
To 'thin' it don't add too much liquid - instead make it creamier by adding more fat. Practice - that's really the key. Find a font you want to try and make a copy to set right in front of you so you can see each stroke as you go.
For practice get that lined paper kindergarteners use to learn writing; write out the letters/words & put plastic over it. Now you can trace over until you feel comfortable doing it w/o tracing it
Also, try using piping gel, melted chocolate (thickened with the *tiniest*/ single drop of water - just thick enough that it doesn't run out of the tip - you have to work quickly when using choco!)