I find that using a ball point pen is easier when tracing on felt fabric. And because the pen can still be evident even after cutting, just be aware which side would be your front side. Ideally your trace marks should appear on the back side of your felt cut out.
Cut out the felt leaves. You can have your leaves without the stem, they look so gorgeous even without it. But if you want the stems on, you can use Aleene’s Foam and Felt glue to stick it on. Another option is to stitch them on.