Today I started actually cutting out frames and along the way I learned a few things.
Firstly, don't try the transome frame first if the transom is angled. This frame will be bevelled and this complicates things a little. If you are still, like me, finding your footing, then this is the most difficult frame to cut and you should pick another to start on.
When you are cutting frames, cut the critical parts slightly long and plane or sand to fit. When you try to cut the notch for the keel shown here, cut it away from the lines you have marked so that there is extra wood. Then lay it out and see how it should fit together. You can easily plane or sand wood away, adding it back can be somewhat tricky.