Anyone experienced can advise me. Some examples pictures would be great.

https://support.garmin.com/en-NZ/?faq=HAajlXN97g6UDuV4QGPDV8&identifier=529896&tab=topics" rel="nofollow - https://support.garmin.com/en-NZ/?faq=HAajlXN97g6UDuV4QGPDV8&identifier=529896&tab=topics

Have definate symbols and clear,doesnt tell me if hungry today or what they are feeding on.

https://www.youtube.com/watch?v=8V5XsZpsziM

I use in 30m or less for structure details,and when it beeps as fish pass by normally get bites, seem important the beam angle as deeper you go the wider the beam,think its set to 17 degrees. Left it to boy to set up.technology is his thing.

Nor all sounders will show fish marks in the same way and I would guess also which transducer you have. Below if shot I took of my Furuno 295 showing snapper & tarakihi. Bottom lock on the left and full depth scale on the right, tarakihi hard on the bottom and snapeer above.

Everybody will interpret what they are looking at differently so it can be hard to explain what you should be lookiing for.

I get pretty good readings on mine although I don't fish really deep, mostly 50 metres or less.

I don't have many pics but heres a recent one in 23m of a snapper haystack on the bottom, you can actually see one of our lines off to the right and 

I'd say that's the softbait or jig being lifted and dropped back far right near the bottom.

Here is a short youtube vid from him about gain settings.

https://www.youtube.com/watch?v=9NsHebS-abw" rel="nofollow - Sensitivity Gain Control (youtube.com)  

I increase gain %, use range, zoom, scroll speed etc depending on conditions.

Its worth learning and playing around with settings as these units can defo provide great readings when tuned right for the conditions.

I believe a lot of reading quality when moving - trolling, searching etc depends on your transducer mounting.

I have set the gain on manual, around 60%, to remove clutter. But I see troutzilla increases the gain over 70%, even with clutter, to see fish sign more clearly. Also - John Adams advises - dont use auto, use around 75%. I will try that.

Second thing - I usually speed to wherever Im going fast, without looking at the sonar, so any fish sign will be missed. When I get where Im interested in, I either anchor, or drift fish, without looking at the sonar. so one reason I havent seen much fish sign, could be I dont look much for it! I should spend some time cruising slowly around where Im interested in, looking for fish sign, before fishing. 

More advice is welcome.

great example of a 'haystack' Jeremy. 

I remember the first time I saw one, out with Redfinger off the Kawau North Channel entrance. I wondered what he was on about, then he showed me the screen and it was unmistakable. 

My understanding is that it indicates the fish are up off the bottom, stacking up and feeding. Seems a bit counter-intuitive, as I assume snapper spread out on the bottom feeding is what you would want to see.

@letsgetem, in terms of 'arches', a penny dropped for me when I saw a YouTube tutorial that pointed out that you only see individual fish 'arches' (what I'd been told were the classic 'slugs' or 'moustache' shapes of snapper) when you're moving along scoping an area looking for sign, but when you turn the engine off and are at a standstill, they represent as waggly unbroken lines.

It's NOT that the fish have disappeared, but the way they show on the screen changes at say, 5kts versus motor off. I was getting frustrated that I could see arches when exploring an area, but as soon as I stopped and dropped lures, the fish seemed to have suddenly gone (in terms of the arches, there were only lines). So once I knew it was just to do with different speeds, I didn't get dispirited.

I've been told you want to see those lines going up and down strongly, not flatlining, again indicating fish are active and feeding. The denser the biomass registering on the sounder, the darker the colour. So big arches, or thick lines at a standstill, indicates a bigger fish - as I understand it. 

What I would also recommend is that you get skilled at understanding SideVu, which is brilliant if you're fishing a shoreline or reef area. It is superb for showing a kind of 3-d model of what's out left or right, which is more useful if softbaiting etc than what's directly under you in that situation.  I found it hard to get my head around the screen image until I watched a tutorial and learned how to interpret what I was seeing, and where the stern of the boat is on the screen, what the black area in the middle is, etc.

I sometimes need to remind myself that what I'm looking at on screen is already behind me, not directly under me. And sometimes I think it's more crucial to identify bait, given the adage 'find the bait, find the fish'. I couldn't believe this image from my Northland trip this year. I think it was golden snapper or something like that, not the big snaps I was seeking. 

The "return" being the air in the swim bladder is a bit of a myth and makes zero sense if you think about it, though there is some suggestion that you may get a stronger return from the swim bladder; not to say you're not getting a return from the rest of the fish.

With a good sounder you can see each hook on a ledger rig at 30m, no swim bladder in there 

Have a read on how sonar works. A 6 inch turd will look exactly the same to a sonar as a 6 inch Blue Cod.