Pot size. Use a pot wide enough to hold all the pieces in one layer. Crowded, they steam instead of searing and the sauce never reduces properly.
On Vegeta. Vegeta and Kucharek are Polish seasoning blends of dried vegetables, salt and MSG, sold in every Polish shop and most large supermarkets. They are what a great many Polish kitchens use in place of stock. If you cannot find either, use a good chicken stock instead and hold back on the salt, since the blends are salty.
The skin. A covered braise will soften the skin, which is the trade for tender meat. If you want it crisp, lift the pieces out once they are cooked, put them under a hot grill skin-side up for a few minutes while the sauce reduces, then return them to serve.