@Lee ********
yeah the onward flight requirement is a nasty one. Very illogical to require visa applicants to first book flights and then decide after whether or not you are even welcome in Thailand. These should be in the opposite order. Various countries that do a better job at this, e.g. Myanmar requires proof of onward travel also if you have a visa, but not at the visa application stage (like in Thailand), but upon entry.
I fully agree to book onward travel tickets at first and then book the real flight later on once you're approved. Although what
@Brandon ***********
says is also true; there isn't really a risk of refusal like there is with visas for European countries, if you just submit all the required docs.