You are a busy bee Isobel!
The big cat is good practice for training the eye to observe - and you've done well here.
The tree across the river pic is a complex one because, I think, the image itself needed sharper tones (the photo) so it calls for the artist to increase the tonal balance (In my opinion!).....i.e. to me, the reflections and tree get lost in each other! Giving the trunk more emphasis in tone and pattern and playing down the reflections of all the greenery would help I think.
There are better penmen (or penpeople!) than I who might help more with the hatching question but I'm not a great lover of cross-hatching ..... I know it's a standard technique but I think it does often look untidy.
For the bank reflections I'd go for vertical line hatching.
For the foliage I'd make foliage-type marks and shapes.
For areas such as the water right under the bank on the right, more solid black - there are areas elsewhere to balance such black bits too.
Hope this helps a bit!