I agree completely with Aurifex about becoming immersed in the authors. It's the only way to become fluent in Latin. It's also very hard and time-consuming. I also agree that a good dictionary with many examples will help more than any other tool. But there is great value in using a composition textbook because it will give you tips that you might not notice while reading. An example, to translate "he said that he would not return," it would not be proper Latin to write: "Dixit se non rediturum esse," but rather "Negavit se rediturum esse." I did not realize this until it was explicitly shown to me in a textbook.
Amice, I am not talking about "reading latin" but "latin prose composition" aspect. Dictionaries of latin synonysm and latin phrase books contain a lot of exemplary sentences from classic authors; they provide comprehensive information on semantic differences between words that appear "very similar in meaning"; they also provide information which vocabulary should be used/ should not be used when composing certain phrase.
A tiny example:
Doderlein (Here is the excerpt from entry "faith" - there is too much for me to rewrite fromt the book so I had to shorten it):
Fides; Fidelitas; Fiducia; Confidentia; Audacia; Audentia. 1.
Fides and
fidelitas mean the fidelity which a man himself observes towards others;
fides, in a more general sense, like πίστις, the keeping of one’s word and assurance from conscientiousness, together with the reliance of others upon us as springing from this quality, the credit we possess;
fidelitas denotes, in a more special sense, like πιστότης, the faithful adherence to persons to whom we have once devoted ourselves; whereas
fiducia and
confidentia denote the trust we place in others;
fiducia, the laudable trust in things, in which we actually can trust, which is allied to the courage of trusting in ourselves, in opp. to
timor; Cic. Div. ii. 31. Plin. Ep. v. 17, like θάρσος; but
confidentia denotes a blamable blind trust, particularly in one’s own strength, in opp. to foresight and discretion, and which converts spirit into presumption, like θράσος. 5.
Fiducia and
confidentia have their foundation in trusting to the prosperous issue of anything;
audacia and
audentia, in the contempt of danger;
audacia sometimes means a laudable boldness, as a word of higher import than
fiducia; sometimes a blamable boldness, as a civil term for
temeritas, like τόλμα; but
audentia is always a laudable spirit of enterprise. Juven. xiii. 108. Quum magna malæ superest
audacia causæ, creditur a multis
fiducia. Sen. Ep. 87. Quæ bona sunt,
fiduciam faciunt, divitiæ
audaciam. (v. 256.)
[...]
446. Fides, Fidelitas; Fidus, Fidelis; Fidentia, Fiducia, Confidentia.
Fides, properly, promise; the honesty in promises and contracts or agreements, if we keep them honestly and conscientiously; and the belief in the
truth of a thing, the holding ourselves convinced of its certainty: Fides est dictorum conventorumque constantia et veritas. Cic. Fidem res habuit. Ovid., it was believed, the thing found belief. Fidelitas , faithfulness, conscientiousness in the fulfilment of one’s duties and calling: Vita mea fideli tate amicorum conservata est. Cic.— Fidus, trustworthy, to be relied upon: Canum fida custodia. Fidelis , faithful, who keeps faith, in whom you may confide : Servi animo fideli in dominum. Cic. — Fidentia, the being confident, self-reliance, the being of good cheer, opp. metus: Fidentia est, per quam magnis et honestis in rebus multum ipse animus in se fiucia certa cum spe collocavit. Cic. Fiducia, confidence : Non modo spem tibi, sed prope certam fiduciam salutis praecebet. Liv. In law language, fiducia signifies the pledge or security for fulfilment of payment, which the creditor receives from the debtor; further, a sale on condition of being permitted to buy back, and the necessary contract respecting the transaction: Qui fiduciam accepit, debet praeslare fidem. Cic. Confidentia, a faulty confidence, boldness, temerity: Videte, quo vultu, qua confident ia dicant; tum inlelligetis, qua religions dicant. Cic. [...]
Ramshorn is even more precise - 10 pages of detail analysis of word "faith".
And this is just the vocabulary analysis, then comes Probst and Meissner - Meissner 10 pages of prose compositional expressions and phrases related to "faith", Probst - about 20 pages.
EDIT:
IMO a win-win soultion is CCELD and Robertson - they serves both as a good "vocabulary dictionary" and "prose composition vocabulary"
