My process (which after years of trying other products / techniques, and failing badly) is;
All these things are relatively cheap via ebay etc...
- Get some VW touch up paint (black magic pearl is code LC9Z). I've always used the genuine stuff, so I can't vouch for anything else.
- Get a meguiars unigrit block. I got a 2000 grit and it works fine. Coarser blocks will require more polishing / sanding to correct the defects.
- Get a glass fibre pencil.
- Get some isopropyl alcohol.
- Clean the chip with IPA. Use the glass fibre pencil to give it a proper clean and remove any loose paint. Clean it after with a microfibre and IPA
- Fill the chip in layers with the paint. To apply it I tend to use one of the brush bristles, plucked out of the brush and taped to a cocktail stick. Some people use a cocktail stick successfully. Either way, the brush is no good - you'll get paint everywhere. Wait for the each layer to dry (maybe 10mins) before applying the next. If you have lots of chips, you might find the first is dry by the time you have painted the last so you can work in a sequence.
- You'll notice the paint will shrink when it dries. You need to keep going until the paint is above the level of the clear coat.
- Once at this level you should let the paint cure properly (maybe a few days).
- Clean the area properly, finishing with IPA
- Using the meguiars unigrit block with lots of water (keep it wet!) sand the chip down until it's level with the clearcoat. Don't be tempted to focus too much on the chip, work in strokes over the area. There are lots of guides on the net.
- Next you need to polish the sanding marks. I've found that with a few passes (using menzerna final finish) using a DA polisher the clear coat is back to perfect.
Anyway, that's a breakdown of what I do once a year. I can't recommend the unigrit block enough, it really simplifies things and helps prevent some pitfalls that can damage your paint.
One thing - it will never look perfect... you'll need a respray for that. It won't be noticeable to anyone apart from you.