The thing to remember is:
Beer brewers take about 6 weeks to finished product. So they can adjust & refine their techniques quite quickly.
If you make cider (traditionally from apples, not supermarket juice), your looking at 1 attempt per year at harvest time, so it takes longer to improve your technique.
For wine making, if you're not using kits, the cycle is often a minimum of 6 months. So don't be put off.
If you have space, time & spare containers(5l spring water bottles are a lot cheaper than demijohns), it might be worth making a batch every couple of months.
Also with wine, there are many fruit combinations to try before you get something that works for you.
I had reasonable success with blackberry & apple made with apple juice & foraged blackberries. Ready in about 6 months & blackberry season should start in a few weeks.
Mashbags advice about oxygen getting in is good too.
If you're working with a 10l wine fermenter, start it with 8l, to allow space for frothing up at the start.
After a couple of weeks, you can top it up to 10l with water (or split into 2 demijohns & top them up)
This is why wine recipies are often 'strong/have a lot of sugar' as you need to dilute them a bit each time you transfer/rack them so the container is full.