One of the trouble spots of my beard is my sideburns. They tend to grow at a faster rate than the rest of my beard which means they need more frequent attention. I usually have to trim my sideburns about once a week or once every two weeks. That's about twice as often as to how often I trim the rest of my beard and mustache.
Sideburns are a strange area of the beard as it is a transition zone of the hair on your hear meeting your beard. For some men this can be a wild and crazy area and for others not so much. When it comes to my sideburns they want to grow out, spiral, and then grow down. Similar to a rams horn. I use my trusted beard and mustache scissors to take the "curse" and curl out of my sideburns so it gives the impression that my beard is just growing straight down.
This is a relatively easy trim but will take some practice to see how your beard and sideburns react to being trimmed. This is a regular maintenance trim for me and have done it hundreds of times. If you're just starting out I'd highly recommend only trimming off tiny sections of hairs, what I like to call "crumbs". I make a more sweeping cut to my sideburn hair as I know how it will react. Remember as always when it comes to trimming your beard, give yourself time, be patient, and use the best quality scissors you can.