To give this a try - whether you are trying to make your own version of something you've seen, or whether it is an idea you've imagined, the best way to start is by trying to draw it - whether or not you think you're good at drawing, the act of looking at (or imagining) the item and trying to figure out how it looks will help you start to think about how it might be build - what shapes join to what, how sections connect, the shape and texture of different elements.. Another way to work is to create a model - depending on the shape you're creating - using paper, card, plasticine, wire to see if you can re-create the form.
Modelmaking and drawing will help you to work out the form, then the next process is to try a prototype - this is a more formal model - made in something close to the final material (if you plan to finally work in gold, then prototype in copper or silver, if you plan to work in silver clay, you could prototype in polymer clay, for example) and working through this will help you to work out and refine any issues. Then you will be ready to create the item for real!
The downside to this process is of course is that you are on your own - but there is plenty of support available, for example - my group the Jewellery Makers - where a friendly group of people is growing - who all love jewellery, and are at different stages of their jewellery making journey - some are professional makers, some are just thinking about getting started, and all different stages in between!
Do come over and join us in the jewellery makers and say hello!
If you've tried teaching yourself something, or working out a new project - do share your own top tips below!!