I just brought home my first bonsai. Looking at some of the guides online I think it needs some pruning after the flowering period. It still has wire on most of the growth. Any suggestions about where to begin are appreciated!
Serissa are popular for bonsai but sadly also easy to kill. There is a lot to know but I will try to focus on how to keep it alive.
Summer: Keep it in a location where it gets a lot of bright light, it loves sun.
Winter: If you live somewhere close to the equator then you can move it to get the most of the winter sun and it can happily keep growing. If however, you live up north or far down south you need to winter it somewhere, this is tricky and means to put it into a state of 'hibernation' where it stops growing. You basically keep the temperature between 2-5 c and the soil moist. If you need to do this, do some research. It is complicated and you need to understand how it works better then I can explain in this answer. If you can not over-winter it in this manner then you need to keep it somewhere where it gets the most sun possible or maybe even use artificial lighting.
Watering: Depending on the soil mixture you should not water too often, try to let the top of the soil dry out a little between watering. When watering, water enough that the entire root ball gets water. If it drops leaves after moving it then give it slightly less water, not more.
Pruning: You can hack away at your Serissa without too much worry of killing it. Just don't prune if it looks unhealthy. It will smell weird when pruned or bruised but this is normal. Pruning is more of a personal choice and how much you cut away and where depends on how you want it to look. Always use a clean pruner.
Wiring: I have not done this with my bonsai trees. However, you should not leave the wire on for more than 4-6 months at a time (as far as I know). If it looks like it is starting to rot under the wires you should remove them immediately. Wiring is an art in its own and you can find a lot of tips by googling it.
Re-potting: Re-pot once every 2-3 years, when re-potting trim the roots and remove all the old soil from between the roots. If you do not use any fertilizer you should re-pot every 1-2 years.
Moving: Try to keep your plant in one place, Serissa are sensitive to changes in their environment and will likely loose leaves if even moved from one room to another. It is ok to move your plant just don't move it too often. Having a summer and winter spot is good, having a different spot for every week is bad. It should stay in the same place for 4-6 weeks before getting moved again.
Fertilizer: If in doubt, don't fertilize. If your plant looks unhealthy, don't fertilize. Only fertilize if your plant is healthy and you have not recently moved it. Over-fertilizing or fertilizing a sick plant is one of the easiest ways to kill a bonsai. If you are unsure then don't use fertilizer, your Serissa is not likely to die if it does not get fertilized. Last but not least you should use bonsai fertilizer not garden fertilizer, bonsai trees have different requirements then garden plants and garden fertilizer can harm (even kill) your bonsai.