Once your panels are in place, keep an eye on them and monitor them regularly. Get to know what you daily output of energy is, what everything looks like when operating optimally and even keep a record of such things. This can help you quickly notice when something isn't working correctly and help you ascertain where the problem is.
The best solar panels are able to be re-positioned to accommodate the seasonal shifting of the sun. But if you have to have a fixed panel, choose the best compromise between positions that you can.
Quick look at my most recent Lidl purchase for the garden, a PID solar spotlight for £7.99.
Going with a solar panel system does not mean that you will be ripping off your roof. You can always start small by purchasing outdoor lighting that is run off of solar energy. They'll charge up during the day to light all night, with exception of pre-dawn hours during long winter nights.