DKR, Weather's advice about the red dot is very useful - the point is to get to know the common birds well. Then, you can always eliminate them very quickly, which leads to another technique - IDing in reverse. Eliminate things! This means a lot of talking to yourself, with sentences that begin with "well, it can't be a xxxx, because it hasn't got an eyestripe,or whatever. There are in fact not many very similar birds that occupy the same habitat at the same altitude in the same place. And don't look at the whole bird, look at specific things, the things that often differentiate similar species. Eyestripe, leg color, wing bars, bill shape etc. You'll quickly eliminate similar lbbs from different groups, such as warblers (here, and there) and finch types. Also, look for color patterns, not just the colors themselves. Don't be put off by the jizzers - jizz is extremely useful (and so overlooked here in the US), but is definitely an experience thing - but just concentrate on a few distinct features. Never miss the opportunity to look carefully at birds you know. Nothing helps with identifying new or difficult birds than a rapid elimination of others; this comes with familiarity of the commoner ones.
If you have 2 or 3 similar birds in your area, study the field guide to find the differences - leg color, lower bill color, crown stripe, whatever - and zoom in on that as soon as you see a target bird, then work to other features to confirm.
Bird calls are similar. Just listen to a call until you can repeat it in your sleep. Even if you don't know the bird. Then when you finally do put the two together, you'll have it for life. Or, at least until winter when the tacker disappears, and you don't hear it for 5 months. but a bit oh refresher work next season will bring it back.
And, actually, most birds (apart from during migration) do hang around the same area, like ducks. If you see a bird in one spot, chances are it'll be back.
Lastly, and most importantly - just pretend juvenile gulls and hawks don't exist, at least for a while yet.
Cheers,
Pemburung