Hi, both my dds were great eaters until we started moving onto chunkier food, then from about 15 mths onwards they were dreadful. It used to get me really wound up, but I always tried not to show it. They ate (healthy) snacks, and weren't underweight or ill, so I just rode it out, and they are now pretty good eaters (at 4 and 3). It has been a long hard slog, though!
basically, I made dinner for all of us every day. I eat with them, and try to resist the urge to say "eat your dinner, eat your dinner, eat your dinner" like a parrot. They are free to eat what they are given or not, although I expect them to at least try it. Often when I've eaten, I leave the table and start clearing the kitchen, as I find they actually eat better when I am not watching them! When it comes to pudding, we have a sliding scale: anyone can request fruit regardless of whether or not they have eaten. If they taste the dinner but refuse to eat it they can have a yoghurt. If they eat some or most, other options come in, depending on how well I think they have done (eg if they eat all the veg but leave the meat or vice versa!) And if they eat it all, I try to have something they really like- like ice cream or cake.
Good luck! Honestly, we are only now coming out the other end, but I'm really glad I persevered. It's also worth trying things- sometimes it's amazing the stuff they like- dd1 won't eat peas or potatoes, but loved fried squid on holiday (not even disguised in breadcrumbs!), and one of the only sandwich fillings she likes is smoked salmon, so worth experimenting.