T.S.
I do my bikini wax myself using Sally Hansen's spa wax. I have found that if you really want good results you need to use a wax that requires heating... those "melt with your body heat" sugar waxes, just can't grab hairs as short as I need them to and end up leaving too much behind. I don't wax anything else as I'm just not willing to let hair grow back between waxes (sparse and fine as it may come in).
If I were you I'd make one more trip to get it done professionally and really focus on what they are doing. That'll probably give you more insight into technique than anything we post here.
Tips:
Make sure the area is clean and dry.
Dust on a (very) little bit of baby powder especially if it's hot where you are.
Heat the wax a bit warmer than they recommend (they don't want you to burn yourself, but thinner is better as long as it isn't scalding and runny).
Do small sections while you get the hang of it.
Pull the strip quickly, then immediately press your hand on the area to avoid pain.
Lidocaine burn ointment works GREAT to avoid redness and irritation.
HTH
T.