Daniel, I'm going to say that they mean pretty much the same thing, you can use them interchangeably without the meaning changing.
The only thing you have to be aware of is using the "-ing" after the preposition "of" and using the infinitive with "to" in the other case.
But one thing is for certain: participating in the forum is a great way of practicing / to practice your English!!!
If you're not sure, do a google search with the expression in " ". I just did one for "a great way of seeing" and "a great way to see". See how many results there are for each option.