Disclaimer: I'm still very new (1st brew done in June) to this so please don't take any of this as gospel, but I wanted to try and give something back to the forum community. Apologies if any of it appears condescending.
SWMBO got me a learn to brew your own beer voucher (after some hints I wanted to start). My LHBS took a half dozen of us through the process of kit brewing, with a whistle stop tour of 3 vessel brewing to create the wort and offered a 10% discount on any purchases made that day.
Maybe I have been lucky but my first 3 (and a bit, bottling tomorrow) brews have gone off without a hitch. Here are some tips from this that have stuck with me and things I have picked up.
1 - Cleanliness, you must sterilise your equipment before use AND clean it properly after use. I keep a wash basin full of steriliser for equipment to sit in and rinse before using while mixing my kits. The LHBS suggested resting equipment on the sterilised lid of your FV as an alternative.
I have been using VWP after using the youngs steriliser that came with my starter kits. (I bought a second after realising it was cheaper than a 2nd barrel and the kit by themselves). When cleaning, starting a new brew or before barrelling, I half fill the FV/barrel with hot water and steriliser, giving a reasonable swirl and using my hands and elbow grease to remove any marks/stains before leaving it to stand for 20mins.
If I have other equipment to clean I leave this in the FV. If the vessel has a tap, I drain half the liquid through the tap, sometimes into bottles if they are still to be added to the collection, before tipping and rotating as I pour the remaining steriliser out. This is also a good chance to clean off any stains from previous brews, I tend to put the lid of my FV in the sink as I rotate and pour.
WORD OF WARNING - check you vessel is empty before tipping - I lost a hydrometer this way.
I then repeat this at least once with water, again draining through a tap and into bottles if appropriate. With bottles I give a good clean with a bottle brush while they are filled with steriliser and then rinse, at least twice before hanging on a bottle tree, while I batch prime and transfer the beer to a bottling vessel or barrel. (I am not looking forward to 40 bottles tomorrow, can see some non rinse steriliser in my future).
Even if I am sure I sterilised something after using it, I sterilise it again before using it.
2 - Patience/details, still one I'm working on TBH. Yes it's exciting getting a new brew on but take your time, give yourself enough time and space and check and double check readings and give the instructions a read - different kits may need more/less sugar may be 30/40pints. I very nearly added the priming sugar instead of the brewing sugar to one kit
.
Before adding the yeast, check the temperature is cool enough for your yeast. I was also advised to aerate the wort, by stirring vigorously for at least 2mins, the yeasties need oxygen to get to work so make sure they've got it - your wort should have a nice frothy head before adding the yeast (the youngs kits I have done have had 15g of yeast and I have not rehydrated the yeast to date).
Once it's in the FV give it time, at least 2 weeks as suggested on here and once bottled barrelled at least another 4 weeks to maximise the taste, that's the hardest part IMHO. Use your hydrometer to check if fermentation has stopped, I tend to siphon into my sample jar, not saying if that is that is the best way to do it though, but my experiment with a tapped FV didn't go to plan (but was rescued) as documented on here.
Keep records - I enter hydrometer readings into my phone calendar and have set up a spreadsheet to calculate abv from these, keep track of costs to date
and cost per litre to date :)
3 - Barrelling/Bottling, lots of advice on here. Having started with barrelling the batch priming makes most sense to me. My first attempt with bottling was last brew where I barrelled most and siphoned off 15 (i think) bottles. After adding the dissolved and cooled sugar to the barrel I placed one tube in the barrel and connected the tube in the FV with the one in the barrel with a tap to minimise splashing. Before removing the tube out of the barrel I then siphoned out what I wanted to bottle, connecting the tap to a bottling wand to ease filling.
WORD OF WARNING - check your barrel/tapped FV is water tight before adding beer, it is not enjoyable seeing your beer drip drip drip away.
When reattaching a tap remember to vaseline the threads and by the washer.
Barrel lids should be vaselined and not overtightened, if you have over tightened a lid, the O ring seal can be reshaped in boiling water if required.
I have also started to double check the brass CO2 valve is tight enough, ie more than finger tight (use a spanner if not).
WORD OF WARNING - taps, check they are closed before adding beer to a vessel, and make sure you know which way is opened/closed when siphoning/pouring. Spilt beer is not enjoyable.
4 - Enjoy it!