Often amateur artists don't know how to ask for critique and more often, they don't know how to receive it in such a way that they can get the maximum benefit from it. There is certainly an art in providing critique which is a topic for another article however, it's equally important to know how to ask for critique in such a way that you maximise your chances of getting useful, actionable advice.
The first few tips will focus around how to ask for critique while the remainder will deal with how to make the best use of the critique that you receive and some situations you may encounter in getting feedback.
Tip 1: Be Specific
When asking for critique, it's important to be specific with what you want help with.
Some good advice for figuring out what this should be is to consider what aspect you had the most trouble with when you were creating the piece. Was it the colours, values, linework, perspective, design?
Occasionally beginners will say "It just looks bad, help?" or that they had trouble with everything. This is not very useful as this tends to elicit very general advice such as "work on your fundamentals" or else the requestor ends up with a dozen different points of improvement. Both of these result in a beginner artist not really knowing where to start.
Tip 2: Don't Single People Out
This is a very common one amongst artists of all levels and it manifests in a couple of ways.
The first is that the requestor specifically singles out a more experienced artist to ask for advice. This in itself is quite rude unless you are specifically receiving mentorship from that person, as you are demanding that person's unpaid time to look over your work, possibly interrupting them from their own.
Another way that this manifests is joining an open channel such as a forum or chatroom and asking the very general question of "Does anyone know about x?" where x could be anything from figure drawing, to shading, to how to draw a cow. When you ask a question like this, you're questioning people's confidence in their abilities and you're unnecessarily excluding people that may be able to help you.
Finally, and probably most rarely of all, requestors will sometimes simply ignore or specifically exclude anyone whose abilities they perceive to be below theirs. This is particularly relevant for structured lessons but can apply to any kind of art. It's important to note that a person's artistic abilities are not directly relevant to their ability to critique - after all, professional art critics are rarely artists themselves. What matters more in a critiquer is their ability to see improvement points and deliver it in a helpful way.
Tip 3: Don't Ask For More Than You've Paid For
It is the absolute height of entitlement to believe that just because you've asked for a free critique, then that means you should get one. If people are providing free critiques, they are generally doing it for your benefit or the benefit of the community you're involved in. They are sacrificing their own time to help you out, so always thank the critiquer for their time whether you agree with their critique or not.
It's okay to ask for clarification on a certain point that a critiquer has provided, however they are under no obligation to continue following up the critique with you. Similarly, demanding that a person redline your work (whether upfront or down the line) is quite rude as this is a further time investment from someone that is not being paid to critique your work. It's okay to ask if they would consider doing a redline to show you how to solve a problem with your drawing but don't be upset if they decline.
Naturally, if the critiquer is being paid to critique you, then there is more that you can ask of them, depending on the specific rules of the agreement as well as whether what you're asking is reasonable compared to the remuneration the critiquer is receiving.
Tip 4: Don't Get Defensive
This one applies to both asking for critique and receiving it. Sometimes artists will be overly critical their own work when asking for critique in a kind of defence mechanism to cut themselves down before anyone else can. Generally this doesn't even work, as those feelings are still raw. It can also have the negative side effect of walling people out from giving you critique because it may seem like you've already covered everything.
It might seem fairly obvious that you shouldn't get defensive when receiving critique, however trying to stop yourself becoming defensive is a lot harder.
People often tie up a lot of their self-worth in the work they produce, so that any criticism or comment upon it can feel like a personal attack - this is perfectly normal, after all, you've worked hard on that piece. This same attachment is what makes it feel so good when we get likes on our social media posts. If you're having trouble remaining objective towards a critique, thank the person that provided it and come back to it later with a clear head. Often doing this helps you see their points from the perspective they were made and sets you on the path to improving your work. If you come back later and look at it objectively and still don't see that the critique has merit, then that's fine, at least you haven't burnt a bridge by getting defensive about it.