Inside: Cheap as chips, good squirt of dish washing detergent in 500mls of water, makes a strong soapy mix.
Using a normal dishwashing sponge, ( flat sqaure cellulose ones, y'know?)dip sponge and wring out well, wipe over all inside glass to leave a thin wet layer. This dries quickly and should cut oily residue off the glass. Bonus is the anti fog properties of the detergent. Repeat if streaky, rinse and wring sponge for each window. If you can still see residue on your inside glass, back off the amount of detergent in the mix.
Outside: microfibre glass cloth with windex to really shift most spots, followed by a coating of rainX. Remove rainX residue with a dripping wet dish sponge, then wipe dry with wrung out sponge.