Active tense. A golden rule for writing texts, equally valuable in drafting contracts as for any text, is to use the active tense instead of the passive. Often, the active voice results in a sentence that is less wordy and more direct.
In passive tense there is the potential danger that it is unclear which party is obliged to perform. To solve this in the passive, the drafter should insert additional words like by Seller. Two additional words. A technique to prevent this is to realise that each obligation should mention the debtor. In most cases, this will almost automatically turn the sentence into the active tense in which the debtor of an obligation is also the (grammatical) subject of the sentence.
Personalise! A method to make contracts dry as dust is to ‘impersonalise’ the contract provisions. Impersonal sentences can be recognised by phrases such as It is agreed that. Often, this phrase is redundant because it would be followed by something like A shall do x and y, which is sufficient and clear. If it is not, the actor (i.e., the debtor of the obligation) is probably missing. Similar examples, in which the debtor potentially remains unclear, start with The Parties agree to.
Similarly, if possible, obligations and other provisions should be drafted in the singular number and the present tense. Instead of The Parties shall promptly notify each other of the occurrence of events of force majeure, it is better to write A Party shall promptly notify the other Party of the occurrence of an event of force majeure.
Nominalisation. Nouns are more tiresome to read than verbs. ‘Active sentences’ tend to build ‘verb-heavy’ structures that would in the passive be covered by nouns. A verb gives a sentence its action, whereas a noun places the reader outside the context. This means that a text also becomes more vivid in the active voice. Not only does the active voice keep a sentence simpler, it also tends to make the sentence clearer.
Lawyers are well able to nominalise verbs: in the lawyer’s eye, a shareholder does not resolve but adopts or makes a resolution; a buyer does not pay but makes a payment; a party does not notify in writing but gives a written notice; a service provider does not act appropriately but takes appropriate action. NOT! Try to avoid these nominalisations and build on verbs as much as possible.