So, what do you need for tools and supplies? 
1) Engine stand 
2) Torque wrench 
3) Replacement oil pan gaskets 
4) Replacement timing chain gaskets 
5) Small amount of silicone sealer/gasket maker 
6) Box/open end, sockets as needed. 
7) Magnetic base and 1" dial-indicator in thousandth's of an inch 
8) Soft Brass hammer 
9) Solvent (lacquer thinner, brake clean, etc.) 
10) Torque specs for your engine. 

Start by draining the oil and removing the oil filer. IF you can, cut the oil filter open and inspect the filter paper. Try and identify the little bits you find. Is it silicone, cork, paper, iron (magnet really helps for this), rubber? Keep track and note what you find in the filter. 

Second, remove the oil pan and oil pump if necessary to inspect the main bearings. 

Next, remove the front cover. At this point, clean any old gasket material from the mating surfaces and scrub them with scrotchbrite and solvent. Set aside to dry. 

Remove the main bearing caps one at a time. Note the location of the tangs on the bearing shells. Remove the shell from the cap clean with solvent and wipe dry with a lint free cloth. I start with number one and move to the back of the engine...but that's just me. Make notes on the condition of the bearing, are there scars from trash or debris passing between the bearing and the crankshaft? The bearing is expendable so it will incur the damage not the crankshaft. Can you feel it if you drag your finger nail across it (LIGHTLY PLEASE!)? Is there any copper showing? Any of these, if extreme will indicate that there is something VERY wrong. Small scratches or groves in the bearing shell are normal. The key word here is SMALL. You should just be able to feel them with your fingernail. 

If it all looks good, wipe and dry the back of the shell and the cap. Insert the shell into the cap and lubricate the shell surface and the crank journal. Place the cap back where it came from and insert the bolts or nuts and washers if using studs. I won't begin to enter into the thoughts on main/rod bolt lubrication for torquing. I prefer to use ARP Moly lube. Some builders use 50w oil. I also use a good assembly lube on the bearings and journals. (Royal Purple is what I've used but Redline has been recommended also. 

In any case, tighten the nuts/bolts to 40ft/lbs and move on to the next main cap. 

NOTE - Before you loosen the thrust main bearing, measure the end-play in the crankshaft. Note this number. Is should be .005" - .010". Yesterday, mine was at .007". The reason for measuring before you remove it is to put it back the way it was. 

Once you have checked all the main shells, set the crankshaft end play and torque all the main nuts/bolts to recommended specifications. On the DART Little-M block it is 65ft/lbs on the mains 1-4 (both inner and outer) and 100ft/lbs on #5 (also the thrust main). 

YOU ENGINE WILL LIKELY NOT BE THE SAME so consult your builder or other documentation. 

I should add here, if you don't feel comfortable doing this, have your engine builder do it. 

Now do the same with the rods. Before loosening any set of rod bolts/nuts, check for side clearance by grabbing the rod caps with your hands and trying to slide them on the rod journal. They should move back and forth easily. If not, you have an issue. Remember, there is about .008" or less clearance between the rod 'cheeks' and the crankshaft throw. This will account for about a total of .024". They are not going to move far, but your should note an audible 'click' when they move from one side to the other. 

When you're done, check the cam shaft from the bottom side (assuming V8 or V6) for tracking or other strange wear pattern or chipping. Inspect the timing gears/chain or just gears. Look for excessive wear, rubbing on the inside of the cover, rubbing on the block, bent or damaged chain links, etc. It may run just fine, until it fails and a piston runs into a valve that was left open at the wrong time. Then......you have a potential for a season ending failure. 

Before you re-install the oil pan. Set the torque wrench and re-check the main bolts/nuts then do the same for the rod bolts/nuts. I do this every time the pan comes off, just before it goes back on the engine. If it's always the LAST THING I do before bolting the pan back on, I know that I remembered to recheck the torque. VERY important if you want the engine to survive. 

Clean is always a good thing when building engines. Keep your tools and hands clean at all times. 

Re-install the oil pump and or any other accessories like the front cover, fuel pump, oil pan, etc. 

Now you can put the engine away for the winter knowing it's ready for the next season.