It is a major frustration if you are constantly running around for little bits and the boat hardly seems to progress. Better planning of the buying trips will reduce the frustration. If you are unsure of your abilities then your work will be hesitant. For most methods of construction you can learn some of the required skills while doing the small bits of preliminary work which are generally needed before you get into the main project. Metal boats need building stocks and frames to be welded together long before you get to the plate welding stage.
Wooden boats have frames and bulkheads to be made up.
For GRP practise you can start with some of the smaller items which will be needed further into the project, like hatch covers, dorade boxes etc. There may be some major new skills which you will need to learn. You may be able to learn them from friends, otherwise consider doing courses at the local technical school. They normally cover such subjects as welding, metalwork, woodwork, electrical and plumbing. If you are planning to build a boat from aluminum then it is particularly important that you educate yourself properly ahead of time.