Boil the milk in a stainless steel pot and stir the milk regularly to make sure it doesn't burn.
Once you make sure that the milk is thoroughly boiling, remove from the heat and add lemon juice. The milk starts curdling right away.
Have another pot ready. Also, you'll need a strainer covered with a cheesecloth.
Scoop the curds and whey (the liquid) into the strainer.
The whey is not used in paneer, but is a useful ingredient in general. You can make lemonade with it, cook your rice with it, use it in steamed vegetable preparations, soups, etc.
The curds should all have remained in the cheesecloth. Wrap the cheesecloth so as to cover the curds completely. Press the cheesecloth a little bit with your hands or a spoon. The point is to squeeze every last bit of whey out of the paneer.
Now you have a block of paneer. This has a good consistency.
When using it in vegetable preps, you'll want to use it in chunks or cubes, sometimes having fried those cubes separately before adding them to the preparation.
Fried paneer cubes are a great addition to rice or peas.