The fuel and the electrical systems are usually the things that most don't think about until its biting them in the backside.
The fuel system is generally pretty straightforward in that you need a pump, filters, fuel line and fittings, however it can get overwhelming pretty quickly. The easiest/cleanest way to do it IMO is get a Tanks Inc. tank (assuming they make one for your car), one of their in-tank pumps (sized to match the engine demand), 2 sets of replacement fuel lines (3/8 feed 5/16 or 3/8 return), then some soft line (rubber, SS braided, nylon braided, etc.) with the fittings to make it work. You can get hard line adapters to adapt the hard line to the soft line which is pretty simple. Then its laying it all out, mounting the 100 micron filter somewhere that you can get to it, mounting the regulator someplace, then installing the line and connecting everything. You also need to use a relay for the fuel pump which will most likely be connected to your EFI ECU.
The electrical system is where most of these conversions fail or cause huge problems to the point that many rip the EFI off and go back to a carb. EFI MUST have good clean steady power and if trying to adapt it to an old wiring harness with a stock style alternator is a sure way to create problems. The electrical system needs to be updated so that the alternator is connected to the battery directly (not through the ammeter), the EFI needs to be connected directly to the battery (both positive and negative sides). The alternator must have enough capacity to power everything and still yield enough steady power for the EFI. This takes some ciphering or calculating to determine what the power (amps and volts) are for the vehicle to allow selecting a compatible alternator.