It's really a matter of personal preference after some preliminary trimming of any branches that are growing horizontal or down. (Dis)proportional cutting is one school of succulent shaping, but you may have your own ideas.

If you search for 'Jade Pruning', 'Whacking a Jade', 'Trimming a Jade', 'Doing the Chopadopoulous with Crassula Ovata*', you will find information ad infinitum. Just search the Forum here Any thread which has lots of replies about whacking would be my first suggestion. You will have lots of pictures (befores and afters even!) and advice / experiences to read about.

*Note that that last suggestion will likely not have any hits