I thought I would describe in short how I started speaking Latin and ultimately came to some kind of "fluency" in the Latin "idiolect" that me and people I often communicate with use*:
1) I double-translated almost all chapters (= lots of Latin text) in
my textbook back into Latin (first into my language and then back to Latin) as many times as needed (before I stopped doing any serious mistakes and I could reproduce the original faithfully). It helped though that besides being a Latin fanatic I was always quite obsessed with typing / typing fast.
2) Having gained these skills to compose Latin sentences almost always correctly (given a good choice of vocabs) I learnt to chat with people (= a written instant communication) quite quickly also. (see my forum signature)
3) Anytime we decided to have a Latin voice chat, I didn't attempt to just try grasping at random words that came to my mind which often results in faltering and constantly broken and slow speech - a very painful and uncomfortable experience for the beginner, since speaking was for me so much different than an instant written chat, but I devised a trick: I either closed my eyes (if I had to) or I did not and I imagined that anything I wanted to express in the spoken conversation I wrote first - I wrote it first in my mind and then I kind of "read" it as I wrote it in my mind. And since my mind was already able to conjugate & decline and compose Latin sentences quickly during writing, I could "fake" quite some fluency sine the early stages even though the mental process was incredibly straining.
4) More often I did this, less I needed to use the trick described in 3 and more my brain adapted to speaking that kind of Latin. In the end I came to a stage where it is not much different to my brain than speaking English in an actual conversation. The only difference is sometimes that one needs to be more creative when it comes to description of some obscure modern stuff (which may have its used neologism, but I may not know it at the moment).
^I just thought someone might be interested
+ It's been a long time since I wrote anything useful in this part of the forum ; -)
* We, of course, try to adapt as classical Latin as possible, though it exhibits itself a little bit better in writing than speaking, where you can use some 'ornate' styles more easily.