I've recently started to enjoy working out. However, my hands often feel achey and fatigued after a good workout (I mainly use various dumbbell exercises). How can I help avoid this?
IF they are truly feeling achey and fatigued then you can reduce the amount of fatigue by continuing to do what you do. As you train you will be developing your muscles involved in gripping the weight.
You could use straps or chalk to help hold the weights in your hand but you should try specifically training your grip first.
These answers give great information on how to train your grip:
TL;DR Train your grip strength specifically.
As you are recently started, as I read from above, I would say that the fatigue is something very normal. Your ligaments and tendons of your hands are going through a process of adoption.
I personally would avoid grip helping utilities until you really start training with heavy weights, as your muscles are taking less time to get used to the stress as your tendons and bones and you will probably cause more issues then avoiding them.
My recommendation would be to rotate the workouts to include an exercise without using 'grip' specific movements ex. Push-ups, sit ups etc. Taking more rest inbetween workouts helps too.
I've recently started to enjoy working out.
then On the answer of this question below, you will find useful info regarding how to improve your grip:
After some time though,
you might find out that you enjoy more lifting heavier weights (some of us do) then for the rows (like one arm dumbbell rows for instance) I would try weight lifting straps, they will reduce the strength you need to put on your grip.
for the pushing exercises, like dumbbell presses, I would try liquid chalk, it helps with your grip.