A new langauge model?

Hi all,

At the moment I'm attempting to create my first conlang (actually it's
more an artlang, I'm making it for a book I'm writing). So far I've
got a few ideas written down, and I thought I'd share them with you, so I
can hear your comments & thoughts on how to change it, improve it, etc.

Anywho, here's the language model so far:
[please bear with me, I'm new to this]

Vowels: a, e, i, o and u (as pronounced in German) as well as
        ae, oe and ue (German vowels with umlauts)

Consonants: d, k, s, p, pf, j, sh, ch, zh, f, t, m, n, r.

Grammar:

Consonants can generally be grouped together without vowels separating
them (?) however only "s", "sh" and "zh" can be placed after "pf".
No more than 3 consecutive vowels are allowed.

I was planning to use a grammatical system similar to Latin,
(with its numerous conjugations and declensions), so that subject, verb
and object could be placed in any order.
As in Latin, pronouns are used only for emphasis, or when necessary for
the meaning of the sentence to be parsed correctly.

Vocabulary: I haven't developed many words so far. Anyone know of any
            software that could help me out here?

...

OK, that's as far as I've gotten. I'm kind of stuck at the moment :)

I'd really appreciate positive criticism here?
Any ideas, people?

Thanks,
Walter Mack
mack@uq.net.au