Also when you’ve produced a good story and the feedback reflects that, it’s a great ego boost! Always look for constructive criticism. Remember you don’t have to agree with all of it (or indeed any) but if your feedback makes you think “ah I had wondered that” (and this has happened a few times to me) then act on that. It can be confirmation you should trust your instincts when writing and should help sharpen your skills.
Beware of groups (online or otherwise) where cliques seem to develop and be aware there are other writers who will seek to criticize destructively (whether from jealousy or insecurity is hard to say). When seeking and getting feedback you should be able to work out “well has this helped me? Can I use this to improve what I do?”. If the answer is no, ignore! And destructive criticism reflects the person making it, not you.
Read, read, read. Not just the professional mags and blogs but novels, short stories, anything you yourself would like to write. You do learn from what you read. Sometimes when you come across a dire piece, you can still learn from it - what not to do! The trick is to make sure that dire piece is not one of yours!
Read contemporary fiction and classic. You need to know what’s going on out there now (and no you won’t keep on top of it all) as well as having a fund of classics which inspire you. After all the classic writers became that way for a reason - they’re good, very good!
Read non-fiction as well as fiction. It may give you ideas to help you populate your fictional world - my Queen’s Chief Leader, L’Evallier, is roughly based on Queen Elizabeth I’s minister, William, Lord Burghley. There I was looking for qualities as well as the similiarities in job. Burghley was not afraid to criticize his boss and always spoke his mind. She knew she needed that. Makes for an interesting relationship - one where there are clashes but there’s always the unspoken question. Will either of them take things too far? Elizabeth almost did after the execution of Mary Stuart when she banished Burghley from Court for a while (and he was devastated by that). L’Evallier becomes more outspoken as the novels go on… will he reach the point of no return?