  In this paper the phase diagram of high $T_{c}$ cuprates is {\it
qualitatively} studied in the context of competing orders: antiferromagnetism,
d-wave superconductivity and $d$-density wave. {\it Local} correlation
functions are estimated from a mean-field solution of the $t-J$ Hamiltonian.
With decreasing doping the superconducting mean-field $T^{MF}_{c}$ and order
parameter $d$ begin to decrease below some characteristic doping $x_{c} \simeq
0.2$ where short-range antiferromagnetic correlations begin to develop. {\it
Dynamical} properties that involve the energy spectrum, such as the normal
state pseudogap, are calculated from effective interactions that are consistent
with the above-mentioned local correlation functions. The total excitation gap
$\Delta_{tg}$ (in the superconducting state) and the normal state pseudogap
$\Delta_{pg}$ are in good agreement with experimental results. Properties of
the condensate are estimated using an effective pairing interaction $V_{eff}$
which takes into account (pair breaking) antiferromagnetic correlations. These
condensate properties include condensation energy U(0), coherence gap
$\Delta_{cg}$ and critical field $H_{c2}$. The calculated coherence gap closely
follows the doping dependence of $T_{c}$ or $d$, and is approximately given as
$\Delta_{cg} \sim \Delta_{tg}-\Delta_{pg}$ within our numerical uncertainties.
The systematic decrease of superfluidity ($d$, U(0), $\Delta_{cg}$, $H_{c2}$),
and systematic increase of $\Delta_{pg}$ and $\Delta_{tg}$ with decreasing
doping below $x_{c}$ have their natural explanation in our approach. The
overall description is however qualitative since it does not appear possible to
obtain results that are in quantitative agreement with experiment for all
physical quantities.
