James, 19, is the younger sister of double Olympic silver medallist Becky and double world para-cycling tandem pilot champion Rachel.
She competes in the women's Under-23 race on Saturday.
James believes she can improve on her 15th place in 2016 event, saying "My big aim is to get top 10."
The 68th Cyclo-Cross World Championships are being held in Belvaux.
"I got some really good training in over the winter and I feel in top form," James told BBC Wales Sport.
Race preparations have been affected by a cold snap, which has left the course covered in snow and ice.
"There have been so many people crashing (in training)," James said.
"There are sheets of ice on some of the corners.
"It's definitely going to level the playing field a little bit.
"People can't just use their strength to ride away from everyone else."
James watched her sister Rachel win silver in the National Track Championships sprint on Friday evening.
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Teenage cyclo-cross rider Ffion James hopes to impress at the World Championships in Luxembourg on Saturday.